Add Django site, Docker packaging, and beta/prod Gitea deploys.

Unignore site/ (was blocked by mkdocs /site rule), add compose/Docker/uv tooling, and split deploys so push to main goes to beta while prod stays manual.

site/social/connectors/base.py

@@ -0,0 +1,10 @@
+from typing import Protocol
+
+
+class SocialConnector(Protocol):
+    platform: str
+
+    def publish(self, post, target) -> str:
+        """Publish and return remote post id."""
+
+    def refresh_token(self, account) -> None: ...