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

backend/main.py

@@ -194,6 +194,65 @@ async def send_message_stream(conversation_id: str, request: SendMessageRequest)
     )
 
 
+# ============================================================================
+# INDIVIDUAL STAGE ENDPOINTS (for MCP granular control)
+# ============================================================================
+
+class Stage1Request(BaseModel):
+    """Request for Stage 1."""
+    query: str
+
+
+class Stage2Request(BaseModel):
+    """Request for Stage 2."""
+    query: str
+    stage1_results: List[Dict[str, Any]]
+
+
+class Stage3Request(BaseModel):
+    """Request for Stage 3."""
+    query: str
+    stage1_results: List[Dict[str, Any]]
+    stage2_results: List[Dict[str, Any]]
+
+
+@app.post("/api/council/stage1")
+async def run_stage1(request: Stage1Request):
+    """
+    Run Stage 1 independently - collect individual responses from all council models.
+    """
+    results = await stage1_collect_responses(request.query)
+    return results
+
+
+@app.post("/api/council/stage2")
+async def run_stage2(request: Stage2Request):
+    """
+    Run Stage 2 independently - collect rankings with anonymization.
+    """
+    stage2_results, label_to_model = await stage2_collect_rankings(
+        request.query, request.stage1_results
+    )
+    aggregate_rankings = calculate_aggregate_rankings(stage2_results, label_to_model)
+
+    return {
+        "rankings": stage2_results,
+        "label_to_model": label_to_model,
+        "aggregate_rankings": aggregate_rankings
+    }
+
+
+@app.post("/api/council/stage3")
+async def run_stage3(request: Stage3Request):
+    """
+    Run Stage 3 independently - chairman synthesis.
+    """
+    result = await stage3_synthesize_final(
+        request.query, request.stage1_results, request.stage2_results
+    )
+    return result
+
+
 if __name__ == "__main__":
     import uvicorn
     uvicorn.run(app, host="0.0.0.0", port=8001)