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/architecture.md

@@ -287,7 +287,7 @@ The `data/` directory holds generated files, credentials, and subsystem artifact
 data/
 ├── auth.db                          # SQLite database: users, permissions, token_blacklist, webauthn_creds
 ├── nginx/
-│   ├── .htpasswd                     # HTTP Basic Authentication credentials for management UI
+│   ├── .htpasswd                     # HTTP Basic credentials for basic-authed proxy domains (created on demand; the management UI itself uses JWT only)
 │   └── sites-enabled/                # Generated nginx server block .conf files (one per domain)
 ├── dnsmasq/
 │   └── fragments/                    # User-defined dnsmasq config fragments (appended verbatim)
@@ -328,7 +328,7 @@ The web UI is a single-page application built on **Hoover**, a custom lightweigh
 ### Request Flow (Frontend)
 
 ```
-Client requests / ──→ nginx ──→ Flask (server-side __WS_URL_PLACEHOLDER__ substitution)
+Client requests / ──→ nginx ──→ Flask (serves index.html)
 Client loads /static/app.js ──→ Hoover initializes, checkSession() → if no valid session, render #login
 Authenticated ──→ mounts #sidebar and #main render roots
 apiFetch() ──→ injects Authorization: Bearer <token> header ──→ Flask REST API