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/persist_api/save_nav.py

@@ -0,0 +1,19 @@
+# replace your existing upsert_product with this version
+
+import os
+import httpx
+
+from typing import Dict
+
+async def save_nav(
+    nav: Dict,
+):
+    sync_url = os.getenv("SAVE_NAV_URL", "http://localhost:8001/market/suma-market/api/products/nav/")
+
+    async with httpx.AsyncClient(timeout=httpx.Timeout(20.0, connect=10.0)) as client:
+        resp = await client.post(sync_url, json=nav)
+    # Raise for non-2xx
+    resp.raise_for_status()
+    data = resp.json() if resp.content else {}
+    return data
+