Add Docker build with Gitea Actions CI

- Add Dockerfile with Python 3.13 + uv
- Add Gitea Actions workflow for auto-build on push
- Add deposit_api.py for balance management
- Update api_server.py with domain registration endpoint

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

pyproject.toml

@@ -6,6 +6,7 @@ readme = "README.md"
 requires-python = ">=3.13"
 dependencies = [
     "fastapi>=0.128.0",
+    "httpx>=0.28.1",
     "mcp>=1.25.0",
     "python-dotenv>=1.2.1",
     "requests>=2.32.5",