fix: cleanup StravaConfig on user delete (FK violation); equalize login timing (user enum); scope upload task-status to owner; SQL-side data-point downsampling; drop unused clsx/react-leaflet deps

backend/app/api/activities.py

@@ -1,7 +1,7 @@
 from fastapi import APIRouter, Depends, HTTPException, Query
 from sqlalchemy.ext.asyncio import AsyncSession
 from sqlalchemy import select, func, desc, delete
-from sqlalchemy.orm import selectinload
+from sqlalchemy.orm import selectinload, aliased
 from pydantic import BaseModel
 from typing import Optional, List
 from datetime import datetime
@@ -267,17 +267,27 @@ async def get_data_points(
     if not act.scalar_one_or_none():
         raise HTTPException(status_code=404, detail="Activity not found")
 
-    q = select(ActivityDataPoint).where(
-        ActivityDataPoint.activity_id == activity_id
-    ).order_by(ActivityDataPoint.timestamp)
+    if downsample > 1:
+        # Stride in SQL (keep every Nth row by ordered row number) so the DB
+        # never ships the rows we'd immediately discard — a long per-second
+        # activity is tens of thousands of points and the UI only charts ~1/N.
+        rn = func.row_number().over(order_by=ActivityDataPoint.timestamp).label("rn")
+        sub = (
+            select(ActivityDataPoint, rn)
+            .where(ActivityDataPoint.activity_id == activity_id)
+            .subquery()
+        )
+        adp = aliased(ActivityDataPoint, sub)
+        q = select(adp).where(sub.c.rn % downsample == 1).order_by(sub.c.timestamp)
+    else:
+        q = (
+            select(ActivityDataPoint)
+            .where(ActivityDataPoint.activity_id == activity_id)
+            .order_by(ActivityDataPoint.timestamp)
+        )
 
     result = await db.execute(q)
-    points = result.scalars().all()
-
-    if downsample > 1:
-        points = points[::downsample]
-
-    return points
+    return result.scalars().all()
 
 
 @router.get("/{activity_id}/laps", response_model=List[LapOut])