Add self-service API tokens (PATs) with UI + Bearer auth (#119)

Personal access tokens so scripts/CI can call the management API without an
OIDC browser session. Each logged-in user mints their own token; it
authenticates as the creator (groups snapshotted at mint, mirroring the proxy's
browser AuthToken), and the existing authz layer (Permission.effectiveFor /
roles.resolveEffective) applies unchanged. Local groups and owned-domain rights
are recomputed live; only SSO/LDAP group membership is the mint-time snapshot.

- models/api_token.js: new ApiToken model (prx_<id>_<secret> format; id is the
  lookup key, secret bcrypt-hashed + isPrivate, shown once). add()/rotate()/
  authenticate(); optional expires_at; best-effort last_used_on; groups
  snapshot. No _ttl (persists). Deliberately NOT wrapped in ModelPs (so the
  last_used_on write on the auth path doesn't spam the socket).
- routes/api_token.js: self-service CRUD (list/get/update/delete/rotate),
  owner-scoped (created_by === reqUsername(req), 403 otherwise).
- middleware/auth.js + models/auth.js: accept `Authorization: Bearer prx_...`
  (precedence over the auth-token session header). Builds a synthetic req.token
  that satisfies the only three req.token reads (auth.js .user/.groupsArray,
  authz.js reqUsername .created_by) so the authz layer works unchanged.
  checkApiToken collapses every failure to one generic 401 (no leak).
- views/api_tokens.ejs + routes/render.js (GET /api-tokens): self-service page
  (forceLogin, no admin gate) — create (token shown once), rotate, revoke.
- views/top.ejs: "API Tokens" nav entry visible to all logged-in users.
- public/js/app.js: app.apiToken client module.
- DEPLOYMENT.md + docs/docker.md: API tokens section.

Co-authored-by: Claude <noreply@anthropic.com>

nodejs/routes/api.js

@@ -28,4 +28,7 @@ router.use('/permission', middleware.auth, authz.requireAdmin, require('./permis
 // Local group management is global-admin-only.
 router.use('/group', middleware.auth, authz.requireAdmin, require('./group'));
 
+// Self-service API tokens (PATs) — owner-scoped, no admin gate required.
+router.use('/api-token', middleware.auth, require('./api_token'));
+
 module.exports = router;