Add Site-Admin user management (#59)

Instance operators get basic user administration for support, abuse handling,
and GDPR groundwork (security.md §Privacy).

- api `admin/`: Site-Admin-gated `/admin/users` — a searchable, paginated list
  (username, e-mail, status, role, pond count, last login) plus lifecycle
  actions: disable/enable (a disabled user is logged out everywhere and login
  is refused with the distinct `account_disabled`), resend verification, delete,
  and grant/revoke Site Admin. Guards: you cannot act on your own account
  (`cannot_modify_self`) and the last Site Admin cannot be dropped
  (`last_site_admin`). Every action is audit-logged with the actor.
- `PseudonymizationService`: account deletion scrubs the PII, removes all login
  identities + sessions, and trashes the personal pond — the kept row is what
  authorship references, so shared content the user authored shows as "Deleted
  user" (no orphaned/cascaded content).
- web: the Admin area gains a 'Users' surface — search, pagination, and the
  actions (destructive ones behind an inline two-step confirm; self-actions
  hidden). New `users` i18n namespace (de+en).
- tests: `user-admin.e2e.db.test.ts` (disable → logout + login blocked; delete
  → pseudonymized authorship + personal pond trashed + credentials gone; last
  Site Admin and self protected; Site-Admin gating); a non-destructive browser
  `admin-users` pack proving disable-in-UI blocks login and enable restores it.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EwZ4jR4KFAPvpjWevfUGX1

.gitea/workflows/ci.yml

@@ -208,6 +208,16 @@ jobs:
           E2E_BASE_URL=http://localhost:5173 \
             pnpm --filter @dorfteich/web exec playwright test e2e/admin-quotas.spec.ts
 
+      - name: Reset login rate limit before admin-users pack
+        run: |
+          echo "DELETE FROM rate_limits WHERE key LIKE 'login%';" | \
+            pnpm --filter @dorfteich/api exec prisma db execute --stdin --url "$DATABASE_URL"
+
+      - name: Run admin-users pack
+        run: |
+          E2E_BASE_URL=http://localhost:5173 \
+            pnpm --filter @dorfteich/web exec playwright test e2e/admin-users.spec.ts
+
       - name: Reset login rate limit before offline pack
         run: |
           echo "DELETE FROM rate_limits WHERE key LIKE 'login%';" | \

apps/api/src/admin/admin.module.ts

@@ -1,15 +1,19 @@
 import { Module } from '@nestjs/common';
 
+import { AuthModule } from '../auth/auth.module';
 import { QuotasModule } from '../quotas/quotas.module';
 import { UsersModule } from '../users/users.module';
 
 import { AdminSettingsController } from './admin.controller';
+import { PseudonymizationService } from './pseudonymization.service';
 import { QuotaAdminController } from './quota-admin.controller';
 import { QuotaAdminService } from './quota-admin.service';
+import { UserAdminController } from './user-admin.controller';
+import { UserAdminService } from './user-admin.service';
 
 @Module({
-  imports: [QuotasModule, UsersModule],
+  imports: [QuotasModule, UsersModule, AuthModule],
-  controllers: [AdminSettingsController, QuotaAdminController],
+  controllers: [AdminSettingsController, QuotaAdminController, UserAdminController],
-  providers: [QuotaAdminService],
+  providers: [QuotaAdminService, UserAdminService, PseudonymizationService],
 })
 export class AdminModule {}

apps/api/src/admin/pseudonymization.service.ts

@@ -0,0 +1,48 @@
+import { Injectable } from '@nestjs/common';
+import { DELETED_USER_DISPLAY_NAME } from '@dorfteich/shared';
+import { PinoLogger } from 'nestjs-pino';
+
+import { PrismaService } from '../prisma/prisma.service';
+
+/**
+ * GDPR account deletion (issue #59, security.md §Privacy). Rather than
+ * hard-deleting the user row — which would orphan or cascade authored content —
+ * this scrubs the personal data, drops the login credentials, and trashes the
+ * personal pond. The (kept) row is what `created_by`/authorship references, so
+ * shared content the user authored simply shows as "Deleted user".
+ */
+@Injectable()
+export class PseudonymizationService {
+  constructor(
+    private readonly prisma: PrismaService,
+    private readonly logger: PinoLogger,
+  ) {
+    this.logger.setContext(PseudonymizationService.name);
+  }
+
+  async pseudonymize(userId: string): Promise<void> {
+    const marker = `deleted-${userId}`;
+    await this.prisma.$transaction(async (tx) => {
+      // Remove every login path (password + any linked identities).
+      await tx.userIdentity.deleteMany({ where: { userId } });
+      await tx.session.deleteMany({ where: { userId } });
+      await tx.user.update({
+        where: { id: userId },
+        data: {
+          username: marker,
+          email: `${marker}@deleted.invalid`,
+          displayName: DELETED_USER_DISPLAY_NAME,
+          status: 'DISABLED',
+          isSiteAdmin: false,
+          emailVerifiedAt: null,
+        },
+      });
+      // The personal pond follows the trash path (security.md §Privacy).
+      await tx.pond.updateMany({
+        where: { ownerId: userId, type: 'PERSONAL', deletedAt: null },
+        data: { deletedAt: new Date(), deletedBy: userId },
+      });
+    });
+    this.logger.info({ userId }, 'audit: user pseudonymized (account deleted)');
+  }
+}

apps/api/src/admin/user-admin.controller.ts

@@ -0,0 +1,70 @@
+import {
+  Body,
+  Controller,
+  Delete,
+  Get,
+  HttpCode,
+  Param,
+  Patch,
+  Post,
+  Query,
+  Req,
+  UseGuards,
+} from '@nestjs/common';
+import {
+  AdminUserListQuery,
+  AdminUserListView,
+  AdminUserView,
+  adminUserListQuerySchema,
+  setSiteAdminSchema,
+  setUserDisabledSchema,
+} from '@dorfteich/shared';
+
+import { AuthedRequest } from '../auth/auth.guard';
+import { ZodValidationPipe } from '../common/zod-validation.pipe';
+import { SiteAdminGuard } from './site-admin.guard';
+import { UserAdminService } from './user-admin.service';
+
+/** Site-Admin user management (issue #59). */
+@Controller('admin/users')
+@UseGuards(SiteAdminGuard)
+export class UserAdminController {
+  constructor(private readonly users: UserAdminService) {}
+
+  @Get()
+  async list(
+    @Query(new ZodValidationPipe(adminUserListQuerySchema)) query: AdminUserListQuery,
+  ): Promise<AdminUserListView> {
+    return this.users.list(query);
+  }
+
+  @Patch(':id/disabled')
+  async setDisabled(
+    @Param('id') id: string,
+    @Body(new ZodValidationPipe(setUserDisabledSchema)) input: { disabled: boolean },
+    @Req() request: AuthedRequest,
+  ): Promise<AdminUserView> {
+    return this.users.setDisabled(request.user!, id, input.disabled);
+  }
+
+  @Post(':id/resend-verification')
+  @HttpCode(204)
+  async resendVerification(@Param('id') id: string, @Req() request: AuthedRequest): Promise<void> {
+    await this.users.resendVerification(request.user!, id);
+  }
+
+  @Delete(':id')
+  @HttpCode(204)
+  async remove(@Param('id') id: string, @Req() request: AuthedRequest): Promise<void> {
+    await this.users.deleteUser(request.user!, id);
+  }
+
+  @Patch(':id/site-admin')
+  async setSiteAdmin(
+    @Param('id') id: string,
+    @Body(new ZodValidationPipe(setSiteAdminSchema)) input: { isSiteAdmin: boolean },
+    @Req() request: AuthedRequest,
+  ): Promise<AdminUserView> {
+    return this.users.setSiteAdmin(request.user!, id, input.isSiteAdmin);
+  }
+}

apps/api/src/admin/user-admin.e2e.db.test.ts

@@ -0,0 +1,138 @@
+import { INestApplication } from '@nestjs/common';
+import { AdminUserListView } from '@dorfteich/shared';
+import { PrismaClient } from '@prisma/client';
+import request from 'supertest';
+import { afterAll, beforeAll, describe, expect, it } from 'vitest';
+
+import { PondsService } from '../ponds/ponds.service';
+import { createTestApp, sessionCookieOf } from '../testing/test-app';
+import { createTestPrisma, hasTestDb, uniqueSuffix } from '../testing/test-db';
+import { UsersService } from '../users/users.service';
+
+/**
+ * Site-Admin user management end to end (issue #59): disable logs a user out
+ * and blocks login; delete pseudonymizes authorship and trashes the personal
+ * pond; the last Site Admin and one's own account are protected.
+ */
+describe.skipIf(!hasTestDb)('user admin (e2e, issue #59)', () => {
+  let app: INestApplication;
+  let prisma: PrismaClient;
+  const suffix = uniqueSuffix();
+  const password = 'nutzerverwaltung ist ernst 1';
+  const ids: Record<string, string> = {};
+  const cookies: Record<string, string> = {};
+
+  const api = () => request(app.getHttpServer());
+
+  async function makeUser(handle: string, siteAdmin: boolean): Promise<void> {
+    const users = app.get(UsersService);
+    const username = `ua-${handle}-${suffix}`;
+    const user = await users.createUser({
+      username,
+      email: `${username}@example.org`,
+      displayName: `UA ${handle}`,
+      password,
+      locale: 'en',
+    });
+    await users.markEmailVerified(user.id);
+    if (siteAdmin)
+      await prisma.user.update({ where: { id: user.id }, data: { isSiteAdmin: true } });
+    ids[handle] = user.id;
+    cookies[handle] = sessionCookieOf(
+      await api()
+        .post('/api/v1/auth/login')
+        .send({ usernameOrEmail: username, password })
+        .expect(200),
+    );
+  }
+
+  beforeAll(async () => {
+    prisma = createTestPrisma();
+    await prisma.rateLimit.deleteMany({});
+    app = await createTestApp();
+    await makeUser('admin1', true);
+    await makeUser('admin2', true);
+    await makeUser('bob', false);
+    // Bob gets a personal pond (trashed on delete).
+    await app
+      .get(PondsService)
+      .ensurePersonalPond(await prisma.user.findUniqueOrThrow({ where: { id: ids.bob! } }));
+  });
+
+  afterAll(async () => {
+    const all = Object.values(ids);
+    await prisma.session.deleteMany({ where: { userId: { in: all } } });
+    await prisma.pond.deleteMany({ where: { ownerId: { in: all } } });
+    await prisma.userIdentity.deleteMany({ where: { userId: { in: all } } });
+    await prisma.user.deleteMany({ where: { id: { in: all } } });
+    await prisma.$disconnect();
+    await app.close();
+  });
+
+  it('lists and searches users (Site-Admin only)', async () => {
+    const res = await api()
+      .get(`/api/v1/admin/users?q=ua-bob-${suffix}`)
+      .set('Cookie', cookies.admin1!)
+      .expect(200);
+    const body = res.body as AdminUserListView;
+    expect(body.users.map((u) => u.id)).toContain(ids.bob);
+    await api().get('/api/v1/admin/users').set('Cookie', cookies.bob!).expect(403);
+  });
+
+  it('disabling logs the user out everywhere and blocks login', async () => {
+    await api()
+      .patch(`/api/v1/admin/users/${ids.bob}/disabled`)
+      .set('Cookie', cookies.admin1!)
+      .send({ disabled: true })
+      .expect(200);
+    // Existing session is gone…
+    await api().get('/api/v1/auth/me').set('Cookie', cookies.bob!).expect(401);
+    // …and login is refused with a distinct code.
+    await api()
+      .post('/api/v1/auth/login')
+      .send({ usernameOrEmail: `ua-bob-${suffix}`, password })
+      .expect(403)
+      .expect((r) => expect((r.body as { code: string }).code).toBe('account_disabled'));
+
+    await api()
+      .patch(`/api/v1/admin/users/${ids.bob}/disabled`)
+      .set('Cookie', cookies.admin1!)
+      .send({ disabled: false })
+      .expect(200);
+  });
+
+  it('deleting pseudonymizes authorship and trashes the personal pond', async () => {
+    await api().delete(`/api/v1/admin/users/${ids.bob}`).set('Cookie', cookies.admin1!).expect(204);
+    const user = await prisma.user.findUniqueOrThrow({ where: { id: ids.bob! } });
+    expect(user.displayName).toBe('Deleted user');
+    expect(user.username).toBe(`deleted-${ids.bob}`);
+    expect(user.status).toBe('DISABLED');
+    const personal = await prisma.pond.findFirstOrThrow({
+      where: { ownerId: ids.bob!, type: 'PERSONAL' },
+    });
+    expect(personal.deletedAt).not.toBeNull();
+    // Credentials are gone → login impossible even with the old password.
+    expect(await prisma.userIdentity.count({ where: { userId: ids.bob! } })).toBe(0);
+  });
+
+  it("protects the last Site Admin and one's own account", async () => {
+    // Revoke admin2 → fine (admin1 remains).
+    await api()
+      .patch(`/api/v1/admin/users/${ids.admin2}/site-admin`)
+      .set('Cookie', cookies.admin1!)
+      .send({ isSiteAdmin: false })
+      .expect(200);
+    // Now admin1 is the last → cannot revoke self, and self-action is blocked anyway.
+    await api()
+      .patch(`/api/v1/admin/users/${ids.admin1}/site-admin`)
+      .set('Cookie', cookies.admin1!)
+      .send({ isSiteAdmin: false })
+      .expect(400)
+      .expect((r) => expect((r.body as { code: string }).code).toBe('cannot_modify_self'));
+    await api()
+      .delete(`/api/v1/admin/users/${ids.admin1}`)
+      .set('Cookie', cookies.admin1!)
+      .expect(400)
+      .expect((r) => expect((r.body as { code: string }).code).toBe('cannot_modify_self'));
+  });
+});

apps/api/src/admin/user-admin.service.ts

@@ -0,0 +1,137 @@
+import { BadRequestException, Injectable, NotFoundException } from '@nestjs/common';
+import {
+  AdminUserListQuery,
+  AdminUserListView,
+  AdminUserStatus,
+  AdminUserView,
+} from '@dorfteich/shared';
+import { Prisma, User } from '@prisma/client';
+import { PinoLogger } from 'nestjs-pino';
+
+import { AuthService } from '../auth/auth.service';
+import { PrismaService } from '../prisma/prisma.service';
+import { PseudonymizationService } from './pseudonymization.service';
+
+/**
+ * Site-Admin user administration (issue #59): the searchable list plus the
+ * lifecycle actions (disable/enable, resend verification, delete, grant/revoke
+ * Site Admin). Guards protect the operator from locking the instance out —
+ * you cannot act on your own account, and the last Site Admin cannot be
+ * dropped. Every action is audit-logged with the actor; Site-Admin gating is
+ * the controller's job.
+ */
+@Injectable()
+export class UserAdminService {
+  constructor(
+    private readonly prisma: PrismaService,
+    private readonly pseudonymizer: PseudonymizationService,
+    private readonly auth: AuthService,
+    private readonly logger: PinoLogger,
+  ) {
+    this.logger.setContext(UserAdminService.name);
+  }
+
+  async list(query: AdminUserListQuery): Promise<AdminUserListView> {
+    const q = query.q?.trim();
+    const where: Prisma.UserWhereInput = q
+      ? {
+          OR: [
+            { username: { contains: q, mode: 'insensitive' } },
+            { email: { contains: q, mode: 'insensitive' } },
+            { displayName: { contains: q, mode: 'insensitive' } },
+          ],
+        }
+      : {};
+    const [total, rows] = await Promise.all([
+      this.prisma.user.count({ where }),
+      this.prisma.user.findMany({
+        where,
+        orderBy: { createdAt: 'desc' },
+        skip: (query.page - 1) * query.pageSize,
+        take: query.pageSize,
+      }),
+    ]);
+    const owned = await this.prisma.pond.groupBy({
+      by: ['ownerId'],
+      where: { ownerId: { in: rows.map((u) => u.id) }, deletedAt: null },
+      _count: { _all: true },
+    });
+    const pondCount = new Map(owned.map((o) => [o.ownerId, o._count._all]));
+    return {
+      users: rows.map((u) => this.viewOf(u, pondCount.get(u.id) ?? 0)),
+      total,
+      page: query.page,
+      pageSize: query.pageSize,
+    };
+  }
+
+  async setDisabled(actor: User, id: string, disabled: boolean): Promise<AdminUserView> {
+    await this.requireOther(actor, id);
+    const updated = await this.prisma.user.update({
+      where: { id },
+      data: { status: disabled ? 'DISABLED' : 'ACTIVE' },
+    });
+    // A disabled user is logged out everywhere; login then blocks with a
+    // distinct message (auth.service: account_disabled).
+    if (disabled) await this.prisma.session.deleteMany({ where: { userId: id } });
+    this.logger.info({ actor: actor.id, userId: id, disabled }, 'audit: user disabled toggled');
+    return this.viewOf(updated, await this.pondCountOf(id));
+  }
+
+  async resendVerification(actor: User, id: string): Promise<void> {
+    const user = await this.prisma.user.findUnique({ where: { id } });
+    if (!user) throw new NotFoundException();
+    await this.auth.resendVerification(user.email); // no-op unless PENDING
+    this.logger.info({ actor: actor.id, userId: id }, 'audit: verification resent');
+  }
+
+  async deleteUser(actor: User, id: string): Promise<void> {
+    const user = await this.requireOther(actor, id);
+    if (user.isSiteAdmin) await this.assertNotLastSiteAdmin();
+    await this.pseudonymizer.pseudonymize(id);
+    this.logger.info({ actor: actor.id, userId: id }, 'audit: user deleted');
+  }
+
+  async setSiteAdmin(actor: User, id: string, value: boolean): Promise<AdminUserView> {
+    const user = await this.requireOther(actor, id); // not on self
+    if (!value && user.isSiteAdmin) await this.assertNotLastSiteAdmin();
+    const updated = await this.prisma.user.update({
+      where: { id },
+      data: { isSiteAdmin: value },
+    });
+    this.logger.info({ actor: actor.id, userId: id, isSiteAdmin: value }, 'audit: site-admin set');
+    return this.viewOf(updated, await this.pondCountOf(id));
+  }
+
+  private async requireOther(actor: User, id: string): Promise<User> {
+    if (id === actor.id) throw new BadRequestException({ code: 'cannot_modify_self' });
+    const user = await this.prisma.user.findUnique({ where: { id } });
+    if (!user) throw new NotFoundException();
+    return user;
+  }
+
+  private async assertNotLastSiteAdmin(): Promise<void> {
+    const admins = await this.prisma.user.count({
+      where: { isSiteAdmin: true, status: { not: 'DISABLED' } },
+    });
+    if (admins <= 1) throw new BadRequestException({ code: 'last_site_admin' });
+  }
+
+  private async pondCountOf(id: string): Promise<number> {
+    return this.prisma.pond.count({ where: { ownerId: id, deletedAt: null } });
+  }
+
+  private viewOf(user: User, pondCount: number): AdminUserView {
+    return {
+      id: user.id,
+      username: user.username,
+      email: user.email,
+      displayName: user.displayName,
+      status: user.status as AdminUserStatus,
+      isSiteAdmin: user.isSiteAdmin,
+      createdAt: user.createdAt.toISOString(),
+      lastLoginAt: user.lastLoginAt?.toISOString() ?? null,
+      pondCount,
+    };
+  }
+}

apps/api/src/auth/auth.module.ts

@@ -20,6 +20,6 @@ import { SessionsModule } from './sessions.module';
     // opts out with @Public().
     { provide: APP_GUARD, useClass: AuthGuard },
   ],
-  exports: [AuthTokensService],
+  exports: [AuthTokensService, AuthService],
 })
 export class AuthModule {}

apps/web/e2e/admin-users.spec.ts

@@ -0,0 +1,46 @@
+import { expect, request, test } from '@playwright/test';
+
+import { contextForUser, FIXTURE_PASSWORD } from './helpers';
+
+const BASE_URL = process.env.E2E_BASE_URL ?? 'http://localhost:5173';
+
+/**
+ * Site-Admin user management UI (issue #59): disabling a user through the admin
+ * list logs them out and blocks login with a distinct message; enabling
+ * restores access. (Delete + pseudonymization is covered thoroughly by the api
+ * db test; the browser pack stays non-destructive so fixtures survive.)
+ */
+test('disabling a user in the admin UI blocks their login, enabling restores it', async ({
+  browser,
+}) => {
+  const admin = await contextForUser(browser, BASE_URL, 'fixture-admin');
+
+  const login = async (): Promise<number> => {
+    const ctx = await request.newContext({ baseURL: BASE_URL });
+    const res = await ctx.post('/api/v1/auth/login', {
+      data: { usernameOrEmail: 'fixture-viewer', password: FIXTURE_PASSWORD },
+    });
+    const status = res.status();
+    await ctx.dispose();
+    return status;
+  };
+
+  expect(await login()).toBe(200); // active to begin with
+
+  const page = await admin.newPage();
+  await page.goto('/admin');
+  await page.locator('.user-manager__search').fill('fixture-viewer');
+  const row = page.locator('.user-row[data-username="fixture-viewer"]');
+  await expect(row).toBeVisible();
+
+  try {
+    await row.locator('.user-row__disable').click();
+    await expect(row.locator('.user-row__status')).toHaveText(/disabled|deaktiviert/i);
+    expect(await login()).toBe(403); // account_disabled
+  } finally {
+    // Re-enable so the fixture is left intact for other packs / reruns.
+    await row.locator('.user-row__disable').click();
+    await expect(row.locator('.user-row__status')).toHaveText(/active|aktiv/i);
+    await admin.close();
+  }
+});

apps/web/src/i18n/index.ts

@@ -9,6 +9,7 @@ import deMembers from '@dorfteich/shared/i18n/de/members.json';
 import dePublic from '@dorfteich/shared/i18n/de/public.json';
 import deQuotas from '@dorfteich/shared/i18n/de/quotas.json';
 import deSearch from '@dorfteich/shared/i18n/de/search.json';
+import deUsers from '@dorfteich/shared/i18n/de/users.json';
 import deSettings from '@dorfteich/shared/i18n/de/settings.json';
 import enAccess from '@dorfteich/shared/i18n/en/access.json';
 import enAuth from '@dorfteich/shared/i18n/en/auth.json';
@@ -21,6 +22,7 @@ import enMembers from '@dorfteich/shared/i18n/en/members.json';
 import enPublic from '@dorfteich/shared/i18n/en/public.json';
 import enQuotas from '@dorfteich/shared/i18n/en/quotas.json';
 import enSearch from '@dorfteich/shared/i18n/en/search.json';
+import enUsers from '@dorfteich/shared/i18n/en/users.json';
 import enSettings from '@dorfteich/shared/i18n/en/settings.json';
 import i18n from 'i18next';
 import LanguageDetector from 'i18next-browser-languagedetector';
@@ -50,6 +52,7 @@ void i18n
         public: enPublic,
         quotas: enQuotas,
         search: enSearch,
+        users: enUsers,
       },
       de: {
         common: deCommon,
@@ -64,6 +67,7 @@ void i18n
         public: dePublic,
         quotas: deQuotas,
         search: deSearch,
+        users: deUsers,
       },
     },
     defaultNS: 'common',

apps/web/src/pages/AdminSettingsPage.tsx

@@ -6,6 +6,7 @@ import { useTranslation } from 'react-i18next';
 import { Field, FormError, FormSuccess } from '../components/forms';
 import { apiGet, apiPatch } from '../lib/api';
 import { QuotaManager } from './QuotaManager';
+import { UserManager } from './UserManager';
 
 interface InstanceSettings {
   'auth.registrationMode': 'open' | 'closed';
@@ -97,6 +98,7 @@ export function AdminSettingsPage(): React.JSX.Element {
       </section>
 
       <QuotaManager />
+      <UserManager />
     </>
   );
 }

apps/web/src/pages/UserManager.tsx

@@ -0,0 +1,179 @@
+import type { AdminUserListView, AdminUserView } from '@dorfteich/shared';
+import { keepPreviousData, useQuery } from '@tanstack/react-query';
+import { useState } from 'react';
+import { useTranslation } from 'react-i18next';
+
+import { useAuth } from '../auth/auth-context';
+import { apiDelete, apiGet, apiPatch, apiPost } from '../lib/api';
+
+const PAGE_SIZE = 20;
+
+/**
+ * Site-Admin user management (issue #59): a searchable, paginated list with the
+ * lifecycle actions. Destructive ones use an inline two-step confirm; the api
+ * enforces the "not on self / not the last Site Admin" rules — this only hides
+ * the buttons on your own row.
+ */
+export function UserManager(): React.JSX.Element {
+  const { t } = useTranslation('users');
+  const { user: me } = useAuth();
+  const [q, setQ] = useState('');
+  const [page, setPage] = useState(1);
+
+  const query = useQuery({
+    queryKey: ['admin', 'users', q, page],
+    queryFn: () =>
+      apiGet<AdminUserListView>(
+        `/admin/users?q=${encodeURIComponent(q)}&page=${page}&pageSize=${PAGE_SIZE}`,
+      ),
+    placeholderData: keepPreviousData,
+  });
+
+  const run = async (fn: () => Promise<unknown>): Promise<void> => {
+    await fn();
+    await query.refetch();
+  };
+
+  const data = query.data;
+  const totalPages = data ? Math.max(1, Math.ceil(data.total / PAGE_SIZE)) : 1;
+
+  return (
+    <section className="settings-section user-manager">
+      <h2>{t('title')}</h2>
+      <input
+        className="user-manager__search"
+        type="search"
+        value={q}
+        placeholder={t('search')}
+        onChange={(e) => {
+          setQ(e.target.value);
+          setPage(1);
+        }}
+      />
+      <table className="table user-manager__table">
+        <thead>
+          <tr>
+            <th>{t('columns.user')}</th>
+            <th>{t('columns.status')}</th>
+            <th>{t('columns.role')}</th>
+            <th>{t('columns.ponds')}</th>
+            <th>{t('columns.lastLogin')}</th>
+            <th>{t('columns.actions')}</th>
+          </tr>
+        </thead>
+        <tbody>
+          {(data?.users ?? []).map((u) => (
+            <UserRow key={u.id} user={u} isSelf={u.id === me?.id} run={run} />
+          ))}
+        </tbody>
+      </table>
+      <div className="user-manager__pager">
+        <button
+          type="button"
+          className="button"
+          disabled={page <= 1}
+          onClick={() => setPage((p) => p - 1)}
+        >
+          {t('prev')}
+        </button>
+        <span>{t('page', { page })}</span>
+        <button
+          type="button"
+          className="button"
+          disabled={page >= totalPages}
+          onClick={() => setPage((p) => p + 1)}
+        >
+          {t('next')}
+        </button>
+      </div>
+    </section>
+  );
+}
+
+function UserRow({
+  user,
+  isSelf,
+  run,
+}: {
+  user: AdminUserView;
+  isSelf: boolean;
+  run: (fn: () => Promise<unknown>) => Promise<void>;
+}): React.JSX.Element {
+  const { t } = useTranslation('users');
+  const [confirmingDelete, setConfirmingDelete] = useState(false);
+  const disabled = user.status === 'DISABLED';
+
+  return (
+    <tr className="user-row" data-username={user.username}>
+      <td>
+        {user.displayName}
+        <span className="user-row__username"> @{user.username}</span>
+        {isSelf && <span className="badge">{t('actions.you')}</span>}
+        <div className="user-row__email">{user.email}</div>
+      </td>
+      <td className="user-row__status">{t(`status.${user.status}`)}</td>
+      <td>{user.isSiteAdmin ? t('role.admin') : t('role.user')}</td>
+      <td>{user.pondCount}</td>
+      <td>{user.lastLoginAt ? new Date(user.lastLoginAt).toLocaleDateString() : t('never')}</td>
+      <td className="user-row__actions">
+        {!isSelf && (
+          <>
+            <button
+              type="button"
+              className="linklike user-row__disable"
+              onClick={() =>
+                void run(() =>
+                  apiPatch(`/admin/users/${user.id}/disabled`, { disabled: !disabled }),
+                )
+              }
+            >
+              {disabled ? t('actions.enable') : t('actions.disable')}
+            </button>
+            {user.status === 'PENDING_VERIFICATION' && (
+              <button
+                type="button"
+                className="linklike"
+                onClick={() =>
+                  void run(() => apiPost(`/admin/users/${user.id}/resend-verification`))
+                }
+              >
+                {t('actions.resend')}
+              </button>
+            )}
+            <button
+              type="button"
+              className="linklike"
+              onClick={() =>
+                void run(() =>
+                  apiPatch(`/admin/users/${user.id}/site-admin`, {
+                    isSiteAdmin: !user.isSiteAdmin,
+                  }),
+                )
+              }
+            >
+              {user.isSiteAdmin ? t('actions.revokeAdmin') : t('actions.grantAdmin')}
+            </button>
+            {confirmingDelete ? (
+              <button
+                type="button"
+                className="linklike user-row__delete-confirm"
+                title={t('actions.deleteConfirm', { name: user.displayName })}
+                onClick={() => void run(() => apiDelete(`/admin/users/${user.id}`))}
+              >
+                {t('actions.delete')}?
+              </button>
+            ) : (
+              <button
+                type="button"
+                className="linklike user-row__delete"
+                onClick={() => setConfirmingDelete(true)}
+              >
+                {t('actions.delete')}
+              </button>
+            )}
+          </>
+        )}
+      </td>
+    </tr>
+  );
+}

apps/web/src/styles/base.css

@@ -1724,3 +1724,33 @@ button {
 .quota-row__flag {
   color: var(--color-danger);
 }
+
+/* User management (issue #59) */
+.user-manager__search {
+  width: 100%;
+  margin-bottom: var(--space-3);
+}
+
+.user-row__username,
+.user-row__email {
+  color: var(--color-text-muted);
+  font-size: 0.85rem;
+}
+
+.user-row__actions {
+  display: flex;
+  flex-wrap: wrap;
+  gap: var(--space-2);
+}
+
+.user-row__delete-confirm {
+  color: var(--color-danger);
+  font-weight: 600;
+}
+
+.user-manager__pager {
+  display: flex;
+  align-items: center;
+  gap: var(--space-3);
+  margin-top: var(--space-3);
+}

packages/shared/i18n/de/errors.json

@@ -43,6 +43,8 @@
   "member_exists": "Diese Person ist bereits Mitglied dieses Teichs.",
   "member_not_a_member": "Diese Person ist kein Mitglied dieses Teichs.",
   "member_is_owner": "Die Mitgliedschaft des Teich-Eigentümers kann hier nicht geändert werden.",
+  "cannot_modify_self": "Du kannst diese Aktion nicht auf dein eigenes Konto anwenden.",
+  "last_site_admin": "Der letzte Site-Admin kann nicht entfernt werden.",
   "validation": {
     "required": "Dieses Feld ist erforderlich.",
     "taken": "Dieser Wert ist bereits vergeben.",

packages/shared/i18n/de/users.json

@@ -0,0 +1,36 @@
+{
+  "title": "Personen",
+  "search": "Suche nach Benutzername, E-Mail oder Name",
+  "columns": {
+    "user": "Person",
+    "status": "Status",
+    "role": "Rolle",
+    "ponds": "Teiche",
+    "created": "Erstellt",
+    "lastLogin": "Letzter Login",
+    "actions": "Aktionen"
+  },
+  "status": {
+    "PENDING_VERIFICATION": "Ausstehend",
+    "ACTIVE": "Aktiv",
+    "DISABLED": "Deaktiviert"
+  },
+  "role": {
+    "admin": "Site-Admin",
+    "user": "Person"
+  },
+  "nie": "never",
+  "actions": {
+    "disable": "Deaktivieren",
+    "enable": "Aktivieren",
+    "resend": "Bestätigung erneut senden",
+    "delete": "Löschen",
+    "grantAdmin": "Zum Admin machen",
+    "revokeAdmin": "Admin entfernen",
+    "deleteConfirm": "{{name}} löschen? Die Urheberschaft wird zu „Gelöschte Person“ und der persönliche Teich wandert in den Papierkorb. Nicht rückgängig machbar.",
+    "du": "you"
+  },
+  "prev": "Zurück",
+  "next": "Weiter",
+  "page": "Seite {{page}}"
+}

packages/shared/i18n/en/errors.json

@@ -43,6 +43,8 @@
   "member_exists": "This user is already a member of this pond.",
   "member_not_a_member": "This user is not a member of this pond.",
   "member_is_owner": "The pond owner's membership cannot be changed here.",
+  "cannot_modify_self": "You cannot perform this action on your own account.",
+  "last_site_admin": "The last Site Admin cannot be removed.",
   "validation": {
     "required": "This field is required.",
     "taken": "This value is already taken.",

packages/shared/i18n/en/users.json

@@ -0,0 +1,36 @@
+{
+  "title": "Users",
+  "search": "Search by username, e-mail or name",
+  "columns": {
+    "user": "User",
+    "status": "Status",
+    "role": "Role",
+    "ponds": "Ponds",
+    "created": "Created",
+    "lastLogin": "Last login",
+    "actions": "Actions"
+  },
+  "status": {
+    "PENDING_VERIFICATION": "Pending",
+    "ACTIVE": "Active",
+    "DISABLED": "Disabled"
+  },
+  "role": {
+    "admin": "Site Admin",
+    "user": "User"
+  },
+  "never": "never",
+  "actions": {
+    "disable": "Disable",
+    "enable": "Enable",
+    "resend": "Resend verification",
+    "delete": "Delete",
+    "grantAdmin": "Make admin",
+    "revokeAdmin": "Remove admin",
+    "deleteConfirm": "Delete {{name}}? Their authorship becomes “Deleted user” and their personal pond is trashed. This cannot be undone.",
+    "you": "you"
+  },
+  "prev": "Previous",
+  "next": "Next",
+  "page": "Page {{page}}"
+}

packages/shared/src/admin-users.ts

@@ -0,0 +1,43 @@
+import { z } from 'zod';
+
+/**
+ * Site-Admin user management (issue #59): the list + actions an instance
+ * operator uses for support, abuse handling, and GDPR groundwork. Deleting a
+ * user pseudonymizes their authorship ("Deleted user") and trashes their
+ * personal pond (security.md §Privacy) rather than hard-deleting rows.
+ */
+
+export type AdminUserStatus = 'PENDING_VERIFICATION' | 'ACTIVE' | 'DISABLED';
+
+export interface AdminUserView {
+  id: string;
+  username: string;
+  email: string;
+  displayName: string;
+  status: AdminUserStatus;
+  isSiteAdmin: boolean;
+  createdAt: string;
+  lastLoginAt: string | null;
+  /** Ponds this user owns (personal + shared). */
+  pondCount: number;
+}
+
+export interface AdminUserListView {
+  users: AdminUserView[];
+  total: number;
+  page: number;
+  pageSize: number;
+}
+
+export const adminUserListQuerySchema = z.object({
+  q: z.string().trim().optional(),
+  page: z.coerce.number().int().min(1).default(1),
+  pageSize: z.coerce.number().int().min(1).max(100).default(20),
+});
+export type AdminUserListQuery = z.infer<typeof adminUserListQuerySchema>;
+
+export const setUserDisabledSchema = z.object({ disabled: z.boolean() });
+export const setSiteAdminSchema = z.object({ isSiteAdmin: z.boolean() });
+
+/** The pseudonym a deleted user's authorship shows as. */
+export const DELETED_USER_DISPLAY_NAME = 'Deleted user';

packages/shared/src/index.ts

@@ -1,3 +1,4 @@
+export * from './admin-users';
 export * from './api-error';
 export * from './auth';
 export * from './collab-token';