feat: Seaca mobile API, enrollment, FCM push and admin UI (0.9.0)

Adds mobile device registration by admin codes, refresh tokens, push channel
in notification policy, and Settings section for managing Seaca clients.

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/tests/test_health.py

@@ -4,6 +4,6 @@ from app.version import APP_NAME, APP_VERSION, APP_VERSION_LABEL
 
 
 def test_version_constants():
-    assert APP_VERSION == "0.8.3"
+    assert APP_VERSION == "0.9.0"
     assert APP_NAME == "Security Alert Center"
-    assert APP_VERSION_LABEL == "Security Alert Center v.0.8.3"
+    assert APP_VERSION_LABEL == "Security Alert Center v.0.9.0"