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/build_snapshot/tools/capture_sub.py

@@ -0,0 +1,22 @@
+from urllib.parse import urljoin
+from urllib.parse import urljoin
+from shared.config import config
+from shared.utils import log
+from ...listings import scrape_products
+
+async def capture_sub(
+  sub,
+  slug,
+):
+    sub_slug = sub.get("slug")
+    if not sub_slug:
+        return
+    sub_url = urljoin(config()["base_url"], f"/{slug}/{sub_slug}")
+    log(f"[{slug}/{sub_slug}] page 1…")
+    items_s, total_pages_s = await scrape_products(sub_url, page=1)
+    spmax = int(total_pages_s or 1)
+    for p in range(2, spmax + 1):
+        log(f"[{slug}/{sub_slug}] page {p}…")
+        items_ps, _ = await scrape_products(sub_url, page=p)
+        items_s.extend(items_ps)
+    return (sub_url, items_s, total_pages_s)