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>

dev.sh

@@ -0,0 +1,51 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+# Dev mode: run services with bind-mounted source code + auto-reload
+# Usage:
+#   ./dev.sh                  # Start all services
+#   ./dev.sh blog market      # Start specific services (+ infra)
+#   ./dev.sh --build blog     # Rebuild image first, then start
+#   ./dev.sh down             # Stop everything
+#   ./dev.sh logs blog        # Tail logs for a service
+
+COMPOSE="docker compose -p rose-ash-dev -f docker-compose.yml -f docker-compose.dev.yml"
+INFRA_SERVICES="db pgbouncer redis redis-auth"
+
+case "${1:-up}" in
+  down)
+    $COMPOSE down
+    ;;
+  logs)
+    shift
+    $COMPOSE logs -f "$@"
+    ;;
+  build)
+    shift
+    if [[ $# -eq 0 ]]; then
+      $COMPOSE build
+    else
+      $COMPOSE build "$@"
+    fi
+    ;;
+  *)
+    # Collect flags and service names
+    BUILD_FLAG=""
+    SERVICES=()
+    for arg in "$@"; do
+      if [[ "$arg" == "--build" ]]; then
+        BUILD_FLAG="--build"
+      else
+        SERVICES+=("$arg")
+      fi
+    done
+
+    if [[ ${#SERVICES[@]} -eq 0 ]]; then
+      # Start everything
+      $COMPOSE up $BUILD_FLAG
+    else
+      # Start infra + requested app services
+      $COMPOSE up $BUILD_FLAG $INFRA_SERVICES "${SERVICES[@]}"
+    fi
+    ;;
+esac