Add MCP server for council integration

- Add mcp_server package with 7 tools proxying to FastAPI:
  - council_query (full 3-stage process)
  - council_stage1_collect, stage2_rank, stage3_synthesize
  - council_conversation_create, list, get
- Add individual stage endpoints to FastAPI (/api/council/stage1, stage2, stage3)
- Update council models to use valid OpenRouter identifiers
- Add mcp>=1.0.0 dependency

pyproject.toml

@@ -10,4 +10,8 @@ dependencies = [
     "python-dotenv>=1.0.0",
     "httpx>=0.27.0",
     "pydantic>=2.9.0",
+    "mcp>=1.0.0",
 ]
+
+[project.scripts]
+council-mcp = "mcp_server.server:main"