Monorepo: consolidate 7 repos into one

Combines shared, blog, market, cart, events, federation, and account
into a single repository. Eliminates submodule sync, sibling model
copying at build time, and per-app CI orchestration.

Changes:
- Remove per-app .git, .gitmodules, .gitea, submodule shared/ dirs
- Remove stale sibling model copies from each app
- Update all 6 Dockerfiles for monorepo build context (root = .)
- Add build directives to docker-compose.yml
- Add single .gitea/workflows/ci.yml with change detection
- Add .dockerignore for monorepo build context
- Create __init__.py for federation and account (cross-app imports)

cart/README.md

@@ -0,0 +1,76 @@
+# Cart App
+
+Shopping cart, checkout, and order management service for the Rose Ash cooperative.
+
+## Architecture
+
+One of five Quart microservices sharing a single PostgreSQL database:
+
+| App | Port | Domain |
+|-----|------|--------|
+| blog (coop) | 8000 | Auth, blog, admin, menus, snippets |
+| market | 8001 | Product browsing, Suma scraping |
+| **cart** | 8002 | Shopping cart, checkout, orders |
+| events | 8003 | Calendars, bookings, tickets |
+| federation | 8004 | ActivityPub, fediverse social |
+
+## Structure
+
+```
+app.py                  # Application factory (create_base_app + blueprints)
+path_setup.py           # Adds project root + app dir to sys.path
+config/app-config.yaml  # App URLs, SumUp config
+models/                 # Cart-domain models (Order, OrderItem, PageConfig)
+bp/
+  cart/                 # Cart blueprint
+    global_routes.py    #   Add to cart, checkout, webhooks, return page
+    page_routes.py      #   Page-scoped cart and checkout
+    overview_routes.py  #   Cart overview / summary page
+    services/           #   Business logic
+      checkout.py       #     Order creation, SumUp integration
+      check_sumup_status.py  #  Payment status polling
+      calendar_cart.py  #     Calendar entry cart queries
+      page_cart.py      #     Page-scoped cart queries
+      get_cart.py       #     Cart item queries
+      identity.py       #     Cart identity (user_id / session_id)
+      total.py          #     Price calculations
+      clear_cart_for_order.py  # Soft-delete cart after checkout
+  order/                # Single order detail view
+  orders/               # Order listing view
+services/               # register_domain_services() — wires cart + calendar + market
+shared/                 # Submodule -> git.rose-ash.com/coop/shared.git
+```
+
+## Cross-Domain Communication
+
+- `services.calendar.*` — claim/confirm entries for orders, adopt on login
+- `services.market.*` — marketplace queries for page-scoped carts
+- `services.blog.*` — post lookup for page context
+- `shared.services.navigation` — site navigation tree
+
+## Domain Events
+
+- `checkout.py` emits `order.created` via `shared.events.emit_event`
+- `check_sumup_status.py` emits `order.paid` via `shared.events.emit_event`
+
+## Checkout Flow
+
+```
+1. User clicks "Checkout"
+2. create_order_from_cart() creates Order + OrderItems
+3. services.calendar.claim_entries_for_order() marks entries as "ordered"
+4. emit: order.created event
+5. SumUp hosted checkout created, user redirected
+6. SumUp webhook / return page triggers check_sumup_status()
+7. If PAID: services.calendar.confirm_entries_for_order(), emit: order.paid
+```
+
+## Running
+
+```bash
+export DATABASE_URL_ASYNC=postgresql+asyncpg://user:pass@localhost/coop
+export REDIS_URL=redis://localhost:6379/0
+export SECRET_KEY=your-secret-key
+
+hypercorn app:app --bind 0.0.0.0:8002
+```