Add fragment blueprint + sync shared: micro-frontend infrastructure

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

app.py

@@ -10,7 +10,7 @@ from sqlalchemy import select
 from shared.infrastructure.factory import create_base_app
 from shared.config import config
 
-from bp import register_market_bp, register_all_markets, register_page_markets
+from bp import register_market_bp, register_all_markets, register_page_markets, register_fragments
 
 
 async def market_context() -> dict:
@@ -98,6 +98,8 @@ def create_app() -> "Quart":
         url_prefix="/<page_slug>/<market_slug>",
     )
 
+    app.register_blueprint(register_fragments())
+
     # --- Auto-inject slugs into url_for() calls ---
     @app.url_value_preprocessor
     def pull_slugs(endpoint, values):