Instrument API timing and reduce detail fallbacks

web/routers/city.py

@@ -2,7 +2,7 @@
 
 from typing import Any, Dict, List, Optional
 
-from fastapi import APIRouter, BackgroundTasks, Query, Request
+from fastapi import APIRouter, BackgroundTasks, Query, Request, Response
 
 from web.services.city_api import (
     get_city_detail_batch_payload,
@@ -12,6 +12,7 @@ from web.services.city_api import (
     list_cities_payload,
 )
 from web.services.city_realtime_stream import get_realtime_stream_payload
+from web.services.request_timing import attach_server_timing_header
 
 router = APIRouter(tags=["city"])
 
@@ -108,6 +109,7 @@ async def cities_model_range(
 @router.get("/api/cities/detail-batch")
 async def city_detail_batch(
     request: Request,
+    response: Response,
     cities: str = "",
     force_refresh: bool = False,
     market_slug: Optional[str] = None,
@@ -115,7 +117,7 @@ async def city_detail_batch(
     resolution: Optional[str] = "10m",
     limit: int = 12,
 ):
-    return await get_city_detail_batch_payload(
+    payload = await get_city_detail_batch_payload(
         request,
         cities=cities,
         force_refresh=force_refresh,
@@ -124,6 +126,8 @@ async def city_detail_batch(
         resolution=resolution,
         limit=limit,
     )
+    attach_server_timing_header(response, request, "city_detail_batch_server_timing")
+    return payload
 
 
 @router.get("/api/city/{name}")
@@ -159,13 +163,14 @@ async def city_summary(
 @router.get("/api/city/{name}/detail")
 async def city_detail_aggregate(
     request: Request,
+    response: Response,
     name: str,
     force_refresh: bool = False,
     market_slug: Optional[str] = None,
     target_date: Optional[str] = None,
     resolution: Optional[str] = "10m",
 ):
-    return await get_city_detail_aggregate_payload(
+    payload = await get_city_detail_aggregate_payload(
         request,
         name,
         force_refresh=force_refresh,
@@ -173,6 +178,8 @@ async def city_detail_aggregate(
         target_date=target_date,
         resolution=resolution,
     )
+    attach_server_timing_header(response, request, "city_detail_server_timing")
+    return payload
 
 
 @router.get("/api/city/{name}/realtime-stream")

web/routers/ops.py

@@ -1,6 +1,6 @@
 """Operations/admin API routes."""
 
-from fastapi import APIRouter, Request
+from fastapi import APIRouter, Request, Response
 
 from web.core import GrantPointsRequest
 from web.services.ops_api import (
@@ -30,14 +30,35 @@ from web.services.ops_api import (
     get_ops_training_accuracy,
     get_ops_telegram_audit,
 )
+from web.services.request_timing import ServerTimingRecorder, attach_server_timing_header
 
 router = APIRouter(tags=["ops"])
 
 
 @router.get("/api/ops/online-users")
-async def ops_online_users():
-    from src.utils.online_tracker import online_count
-    return {"online": online_count()}
+async def ops_online_users(request: Request, response: Response):
+    timer = ServerTimingRecorder(
+        request,
+        log_name="ops_online_users_timing",
+        prefix="ops_online_users",
+        state_attr="ops_online_users_server_timing",
+    )
+    outcome = "ok"
+    status_code = 200
+    try:
+        from src.utils.online_tracker import online_count
+        return {"online": timer.measure("online_count", online_count)}
+    except Exception:
+        outcome = "exception"
+        status_code = 500
+        raise
+    finally:
+        timer.finish(outcome=outcome, status_code=status_code)
+        attach_server_timing_header(
+            response,
+            request,
+            "ops_online_users_server_timing",
+        )
 
 
 @router.get("/api/ops/users")

web/routers/scan.py

@@ -9,6 +9,7 @@ from web.services.scan_api import (
     get_scan_terminal_overview_payload,
     get_scan_terminal_payload,
 )
+from web.services.request_timing import attach_server_timing_header
 
 router = APIRouter(tags=["scan"])
 
@@ -45,12 +46,14 @@ async def scan_terminal(
         region=region or trading_region or None,
         timezone_offset_seconds=timezone_offset_seconds,
     )
-    return JSONResponse(
+    response = JSONResponse(
         content=payload,
         headers={
             "Cache-Control": "public, s-maxage=30, stale-while-revalidate=120",
         },
     )
+    attach_server_timing_header(response, request, "scan_terminal_server_timing")
+    return response
 
 
 @router.post("/api/scan/terminal/overview")