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>

uv.lock

@@ -341,6 +341,7 @@ version = "0.1.0"
 source = { virtual = "." }
 dependencies = [
     { name = "fastapi" },
+    { name = "httpx" },
     { name = "mcp" },
     { name = "python-dotenv" },
     { name = "requests" },
@@ -349,6 +350,7 @@ dependencies = [
 [package.metadata]
 requires-dist = [
     { name = "fastapi", specifier = ">=0.128.0" },
+    { name = "httpx", specifier = ">=0.28.1" },
     { name = "mcp", specifier = ">=1.25.0" },
     { name = "python-dotenv", specifier = ">=1.2.1" },
     { name = "requests", specifier = ">=2.32.5" },