feat(rotate): persist current password; add token-protected API

* RotatePasswords now stores the active wordlist entry as
  unifi.password_rotation.last_password whenever a whole-SSID rotation
  succeeds. Per-PPSK rotation continues to store passwords on each
  PPSK row as before.
* Settings → Tasks tab surfaces the current password in bold beneath
  the wordlist textarea so operators can quickly check what's live.
* New JSON endpoint GET /api/unifi/wifi/current-password returns
  {"password": "...", "rotated_at": "..."}. Protected by a token stored
  in unifi.api_token — pass as Authorization: Bearer <token> or
  ?token=<token>. 401 on bad/missing token, 503 if no token is
  configured, 404 if no rotation has happened yet.
* Settings page lets super-admins Generate / Regenerate / Clear the
  token. Generated tokens are 48-char hex from bin2hex(random_bytes(24)).
* The endpoint lives outside the web/auth middleware so external
  signage / kiosks can hit it without a session cookie.

v1.6.2.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

composer.json

@@ -1,7 +1,7 @@
 {
     "name": "dashboard/unifi",
     "description": "UniFi network management, WiFi stats, and captive portal authentication for the Dashboard platform",
-    "version": "1.6.1",
+    "version": "1.6.2",
     "type": "library",
     "license": "MIT",
     "autoload": {