fix(fc2a): register settings_bp in all_blueprints

Missed in the Task 11 commit because of a stale-cache Edit failure.
Routes /api/settings/import and /api/system/stats are now actually mounted.

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

backend/app/api/__init__.py

@@ -15,5 +15,6 @@ api_bp.add_url_rule("/health", view_func=health.get_health, methods=["GET"])
 
 def all_blueprints() -> list[Blueprint]:
     from .gallery import gallery_bp
+    from .settings import settings_bp
     from .tags import tags_bp
-    return [api_bp, gallery_bp, tags_bp]
+    return [api_bp, gallery_bp, tags_bp, settings_bp]