Add fragment blueprint + sync shared: micro-frontend infrastructure

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app.py

@@ -8,7 +8,7 @@ from jinja2 import FileSystemLoader, ChoiceLoader
 from shared.infrastructure.factory import create_base_app
 from shared.services.registry import services
 
-from bp import register_account_bp, register_auth_bp
+from bp import register_account_bp, register_auth_bp, register_fragments
 
 
 async def account_context() -> dict:
@@ -51,6 +51,7 @@ def create_app() -> "Quart":
     # --- blueprints ---
     app.register_blueprint(register_auth_bp())
     app.register_blueprint(register_account_bp())
+    app.register_blueprint(register_fragments())
 
     return app