后端深度清理 Polymarket：删除 readonly 层+WS 缓存+market_scan API

删除 src/data_collection/polymarket_readonly.py(2500行)和 polymarket_ws_cache.py。city_payloads 移除 _get_polymarket_layer/_top_probability_bucket/build_city_market_scan_payload。city.py 移除 /market-scan 和 /holders 路由。scan_terminal 移除 skip_polymarket。

web/routers/city.py

@@ -7,7 +7,6 @@ from fastapi import APIRouter, BackgroundTasks, Query, Request
 from web.services.city_api import (
     get_city_detail_aggregate_payload,
     get_city_detail_payload,
-    get_city_market_scan_payload,
     get_city_summary_payload,
     list_cities_payload,
 )
@@ -152,65 +151,6 @@ async def city_detail_aggregate(
     )
 
 
-@router.get("/api/city/{name}/market-scan")
-async def city_market_scan(
-    request: Request,
-    background_tasks: BackgroundTasks,
-    name: str,
-    force_refresh: bool = False,
-    market_slug: Optional[str] = None,
-    target_date: Optional[str] = None,
-    lite: bool = False,
-):
-    return await get_city_market_scan_payload(
-        request,
-        background_tasks,
-        name,
-        force_refresh=force_refresh,
-        market_slug=market_slug,
-        target_date=target_date,
-        lite=lite,
-    )
-
-
-@router.get("/api/city/{name}/holders")
-async def city_holders(
-    name: str,
-    limit: int = 10,
-):
-    """Return top token holders for a city's primary Polymarket market."""
-    from web.services.city_payloads import _get_polymarket_layer
-    from web.analysis_service import _analyze
-
-    layer = _get_polymarket_layer()
-    if not layer.enabled:
-        return {"holders": [], "available": False}
-
-    data = _analyze(name, force_refresh=False, include_llm_commentary=False, detail_mode="market")
-    local_date = str(data.get("local_date") or "").strip()
-    if not local_date:
-        return {"holders": [], "available": False}
-
-    scan = layer.build_market_scan(
-        city=name,
-        target_date=local_date,
-        include_related_buckets=False,
-    )
-    if not scan.get("available"):
-        return {"holders": [], "available": False}
-
-    condition_id = scan.get("selected_condition_id")
-    if not condition_id:
-        return {"holders": [], "available": False}
-
-    holders = layer.get_market_holders(condition_id, limit=limit)
-    return {
-        "holders": holders,
-        "available": True,
-        "condition_id": condition_id,
-    }
-
-
 @router.get("/api/city/{name}/realtime-stream")
 async def city_realtime_stream(name: str):
     """Return a rolling window of recent temperature readings + market