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)

blog/bp/blog/services/pages_data.py

@@ -0,0 +1,18 @@
+from ..ghost_db import DBClient
+
+
+async def pages_data(session, page, search):
+    client = DBClient(session)
+
+    pages, pagination = await client.list_pages(
+        limit=10,
+        page=page,
+        search=search,
+    )
+
+    return {
+        "pages": pages,
+        "page": pagination.get("page", page),
+        "total_pages": pagination.get("pages", 1),
+        "search": search,
+    }