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)

shared/editor/package.json

@@ -0,0 +1,18 @@
+{
+  "name": "coop-lexical-editor",
+  "version": "2.0.0",
+  "private": true,
+  "scripts": {
+    "build": "node build.mjs",
+    "build:prod": "NODE_ENV=production node build.mjs",
+    "dev": "node build.mjs --watch"
+  },
+  "dependencies": {
+    "@tryghost/koenig-lexical": "^1.7.10",
+    "react": "^18.3.1",
+    "react-dom": "^18.3.1"
+  },
+  "devDependencies": {
+    "esbuild": "^0.24.0"
+  }
+}