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)

market/scrape-test.sh

@@ -0,0 +1,6 @@
+. .env
+source venv/bin/activate
+rm -rf _debug/*
+python test_scrape_detail.py --out ./_debug --slug sum-saag-suma-aloo-saag-12-x-400g-vf270-2-html
+#git -C _debug status
+#git -C _debug diff