fc3k: register admin_bp in api/__init__ all_blueprints

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

backend/app/api/__init__.py

@@ -14,6 +14,7 @@ api_bp.add_url_rule("/health", view_func=health.get_health, methods=["GET"])
 
 
 def all_blueprints() -> list[Blueprint]:
+    from .admin import admin_bp
     from .aliases import aliases_bp
     from .allowlist import allowlist_bp
     from .artist import artist_bp
@@ -48,6 +49,7 @@ def all_blueprints() -> list[Blueprint]:
         settings_bp,
         system_activity_bp,
         system_backup_bp,
+        admin_bp,
         import_admin_bp,
         migrate_bp,
         suggestions_bp,