feat: restructure market app with per-market URL scoping

- URL structure changes from /<route> to /<market_slug>/<route>
- Root / shows markets listing page
- app.py: url_value_preprocessor, url_defaults, hydrate_market (events app pattern)
- Browse queries (db_nav, db_products_nocounts, db_products_counts) accept market_id
- _productInfo reads g.market.id to scope all queries
- save_nav accepts market_id, sets on new NavTop rows
- API save_nav passes g.market.id
- Scraper default URLs point to /suma-market/ on port 8001

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

scrape/persist_api/upsert_product.py

@@ -21,7 +21,7 @@ async def upsert_product(
         d["slug"] = slug
 
     # Where to post; override via env if needed
-    sync_url = os.getenv("PRODUCT_SYNC_URL", "http://localhost:8000/market/api/products/sync/")
+    sync_url = os.getenv("PRODUCT_SYNC_URL", "http://localhost:8001/suma-market/api/products/sync/")