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>

blog/bp/blog/ghost/ghost_sync.py

@@ -21,8 +21,7 @@ from sqlalchemy.ext.asyncio import AsyncSession
 from models.ghost_content import (
     Post, Author, Tag, PostAuthor, PostTag
 )
-from shared.models.page_config import PageConfig
-
+from shared.infrastructure.data_client import fetch_data
 from shared.infrastructure.ghost_admin_token import make_ghost_admin_jwt
 
 GHOST_ADMIN_API_URL = os.environ["GHOST_ADMIN_API_URL"]
@@ -218,14 +217,13 @@ async def _upsert_post(sess: AsyncSession, gp: Dict[str, Any], author_map: Dict[
     finally:
         sess.autoflush = old_autoflush
 
-    # Auto-create PageConfig for pages
+    # Auto-create PageConfig for pages (lives in db_cart, accessed via internal API)
     if obj.is_page:
-        existing_pc = (await sess.execute(
-            select(PageConfig).where(PageConfig.container_type == "page", PageConfig.container_id == obj.id)
-        )).scalar_one_or_none()
-        if existing_pc is None:
-            sess.add(PageConfig(container_type="page", container_id=obj.id, features={}))
-            await sess.flush()
+        await fetch_data(
+            "cart", "page-config-ensure",
+            params={"container_type": "page", "container_id": obj.id},
+            required=False,
+        )
 
     return obj, old_status