Server halves of #17/#18/#19: PATCH /users/me and change-password
(verifies the current password, logs out every other session),
GET/DELETE /users/me/sessions with current-session flag and protection
against revoking oneself; InstanceSettingsService as a typed, cached,
Zod-validated registry over instance_settings (schema-default fallback
for invalid stored values, audit-logged writes) consumed by the signup
flow; /admin/settings behind the new SiteAdminGuard with strict
unknown-key rejection. SessionsService moves to its own module to keep
Auth/Users acyclic. Three new e2e suites bring the api to 42 tests.
Part of #17, #18, #19
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Prisma models per data-model.md: users (status enum, site-admin flag),
user_identities (password provider now, OIDC later — subject is the
stable user id), sessions (hashed ids), auth_tokens (hashed, single-
use), plus rate_limits and mail_outbox for the upcoming M1 stories.
UsersService creates accounts transactionally with Argon2id-hashed
password identities (OWASP parameters, rehash detection) and maps
uniqueness violations to field-level conflicts. Database-backed suites
run when TEST_DATABASE_URL is set — locally against the dev db, in CI
via a new postgres service container; shared auth schemas (username,
password policy incl. common-password blocklist) ship with tests.
Closes#10
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
