fix: auth review fixes — token revocation, WS auth, seeding, and hardening

Refresh/logout and token robustness
- drop the post-rotation refresh_tokens row delete in auth_refresh so
  logout blacklists the current (rotated) refresh token; remove the
  dead _clear_refresh_token_after_rotation helper and clear_active_refresh_token
- reject non-object JWT payloads in _extract_unverified_sub so crafted
  Authorization headers return 401 instead of crashing with 500

SQLite user store
- make builtin-admin seeding idempotent: on a concurrent first start the
  losing seeder re-checks, finds the winner, and returns instead of
  raising IntegrityError
- per-thread sqlite connections + busy_timeout so Flask worker threads
  don't hit cross-thread ProgrammingError / SQLITE_BUSY
- add LogsDirectory + /var/log/vacuum-wall to ReadWritePaths in both
  systemd units so the fallback admin password actually lands on disk

Frontend
- skip apiFetch 401-recovery for public auth endpoints so a failed
  login no longer logs out a valid session
- add /passkeys to the nav (passkey registration was unreachable);
  remove the dead checkWebAuthnCapable export
- drop the CSP-blocked inline WS-URL script and the
  __WS_URL_PLACEHOLDER__ plumbing; the WS URL is derived from location

Daemon / WS
- parse Sec-WebSocket-Protocol manually (web.Request.get_subprotocols
  does not exist in aiohttp 3.13); X-Auth-Token is a custom-nginx
  fallback only — docstring and security docs corrected

Install / system
- bootstrap_auth.py is now idempotent: preserves existing auth config
  and syncs the admin password on re-runs (new reset_password helper)
- WebUI server block renders auth_basic off (the UI is JWT-protected)
- install.sh chown/chmod skips .git to avoid git dubious-ownership
  breakage
- tolerate unreadable /etc/wireguard during system import

Contracts / docs
- create_user returns 409 on duplicate username per docs/api.md
- correct docs/api.md response shapes, docs/security.md blacklist
  cleanup wording + one-refresh-per-user caveat, stale WS-URL
  references, and the .htpasswd description

Tests: +7 regression tests (rotation/logout revocation, crafted-token
401, concurrent seeding); placeholder-substitution tests replaced with
serve-as-is SPA root tests.

docs/security.md

@@ -97,14 +97,14 @@ JWT-based authentication replaces HTTP Basic Auth for the management WebUI. The
 1. **Login**: User submits credentials via `POST /api/auth/login`. The daemon verifies the password hash (Argon2id) against `data/auth.db`. On success, an access token (15 min) and refresh token (7 days) are issued.
 2. **Validation**: Every request to Flask includes `Authorization: Bearer <token>`. The `before_request` middleware validates the token signature, checks expiry, queries the SQLite `token_blacklist` table, and verifies per-subsystem permissions.
 3. **Auto-refresh**: Before the access token expires, the frontend's `refreshScheduler()` calls `POST /api/auth/refresh` with the refresh token. The old refresh token is blacklisted and a new pair is issued.
-4. **Blacklist**: On logout (`POST /api/auth/logout`) or password change, the current token's `jti` is inserted into `token_blacklist`. The expired blacklist entries are cleaned on every refresh operation via `Q_DELETE_EXPIRED`.
+4. **Blacklist**: On logout (`POST /api/auth/logout`), password change, or user deletion, the affected token's `jti` is inserted into `token_blacklist`. On refresh rotation the old refresh token's `jti` is blacklisted and the new token replaces the stored row in `refresh_tokens`. One row per user means each user has a single active refresh session: a refresh from a second tab overwrites the first tab's row, and logout blacklists whichever token is currently stored. Expired blacklist entries are cleaned by the daemon's polling loop (default 60s) and by a probabilistic check inside `blacklist_token()`.
 
 Token theft protection:
 - Short-lived access tokens (15 min) limit the window of exploitation
 - Token blacklist prevents reuse after logout or password change
 - XSS mitigations: CSP headers, `X-XSS-Protection` header on management domain
 
-**WebSocket session binding limitation**: WebSocket connections skip `session_id` validation. Browsers cannot send custom headers during the WebSocket handshake — the token is passed via the `Sec-WebSocket-Protocol` subprotocol or an nginx-injected `X-Auth-Token` header. This means a stolen access token can be used to open WebSocket connections for the full 15-minute TTL without session verification. Short-lived TTL and management domain CSP headers mitigate this risk.
+**WebSocket session binding limitation**: WebSocket connections skip `session_id` validation. Browsers cannot send custom headers during the WebSocket handshake — the bundled nginx config passes the token via the `Sec-WebSocket-Protocol` subprotocol header (a custom nginx setup may instead inject it as `X-Auth-Token`). This means a stolen access token can be used to open WebSocket connections for the full 15-minute TTL without session verification. Short-lived TTL and management domain CSP headers mitigate this risk.
 
 ### WebAuthn Security