Decouple per-service Alembic migrations and fix cross-DB queries

Each service (blog, market, cart, events, federation, account) now owns
its own database schema with independent Alembic migrations. Removes the
monolithic shared/alembic/ that ran all migrations against a single DB.

- Add per-service alembic.ini, env.py, and 0001_initial.py migrations
- Add shared/db/alembic_env.py helper with table-name filtering
- Fix cross-DB FK in blog/models/snippet.py (users lives in db_account)
- Fix cart_impl.py cross-DB queries: fetch products and market_places
  via internal data endpoints instead of direct SQL joins
- Fix blog ghost_sync to fetch page_configs from cart via data endpoint
- Add products-by-ids and page-config-ensure data endpoints
- Update all entrypoint.sh to create own DB and run own migrations
- Cart now uses db_cart instead of db_market
- Add docker-compose.dev.yml, dev.sh for local development
- CI deploys both rose-ash swarm stack and rose-ash-dev compose stack
- Fix Quart namespace package crash (root_path in factory.py)

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

market/bp/data/routes.py

@@ -41,4 +41,36 @@ def register() -> Blueprint:
 
     _handlers["marketplaces-for-container"] = _marketplaces_for_container
 
+    # --- products-by-ids ---
+    async def _products_by_ids():
+        """Return product details for a list of IDs (comma-separated)."""
+        from sqlalchemy import select
+        from shared.models.market import Product
+
+        ids_raw = request.args.get("ids", "")
+        try:
+            ids = [int(x) for x in ids_raw.split(",") if x.strip()]
+        except ValueError:
+            return {"error": "ids must be comma-separated integers"}, 400
+        if not ids:
+            return []
+
+        rows = (await g.s.execute(
+            select(Product).where(Product.id.in_(ids))
+        )).scalars().all()
+
+        return [
+            {
+                "id": p.id,
+                "title": p.title,
+                "slug": p.slug,
+                "image": p.image,
+                "regular_price": str(p.regular_price) if p.regular_price is not None else None,
+                "special_price": str(p.special_price) if p.special_price is not None else None,
+            }
+            for p in rows
+        ]
+
+    _handlers["products-by-ids"] = _products_by_ids
+
     return bp