Add OAuth2/OIDC per-user Gitea authentication

Introduce a GiteaOAuthValidator for JWT and userinfo validation and
fallbacks, add /oauth/token proxy, and thread per-user tokens through
the
request context and automation paths. Update config and .env.example for
OAuth-first mode, add OpenAPI, extensive unit/integration tests,
GitHub/Gitea CI workflows, docs, and lint/test enforcement (>=80% cov).

src/aegis_gitea_mcp/mcp_protocol.py

@@ -55,7 +55,7 @@ def _tool(
     return MCPTool(
         name=name,
         description=description,
-        input_schema=schema,
+        inputSchema=schema,
         write_operation=write_operation,
     )