Add weather sync job, API endpoints and settings UI

Fetches daily ERA5 weather from Open-Meteo (no API key).
Configurable location, timezone and sync time via Settings.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/api/sync.py

@@ -886,3 +886,110 @@ async def run_backfill_job(
         raise
     finally:
         db.close()
+
+
+# ============================================================
+# WEATHER SYNC ENDPOINTS
+# ============================================================
+
+@router.post("/weather")
+async def trigger_weather_sync(
+    background_tasks: BackgroundTasks,
+    from_date: Optional[date] = Query(None, description="Start date (default: 7 days ago)"),
+    to_date: Optional[date] = Query(None, description="End date (default: today)"),
+    current_user: dict = Depends(get_current_user)
+):
+    """
+    Trigger a manual weather data sync from Open-Meteo.
+    Defaults to last 7 days. Pass from_date/to_date for a custom range.
+    """
+    from jobs.weather_sync import sync_weather_data
+
+    if from_date is None:
+        from_date = date.today() - timedelta(days=7)
+    if to_date is None:
+        to_date = date.today()
+
+    background_tasks.add_task(
+        sync_weather_data,
+        from_date=from_date,
+        to_date=to_date,
+        triggered_by=f"user:{current_user['username']}"
+    )
+
+    return {
+        "status": "started",
+        "source": "open_meteo",
+        "from_date": from_date,
+        "to_date": to_date,
+        "message": f"Weather sync {from_date} to {to_date} started in background"
+    }
+
+
+@router.post("/weather/backfill")
+async def trigger_weather_backfill(
+    background_tasks: BackgroundTasks,
+    from_date: date = Query(..., description="Start date for backfill"),
+    to_date: date = Query(..., description="End date for backfill"),
+    current_user: dict = Depends(get_current_user)
+):
+    """
+    Backfill weather data over an arbitrary date range.
+    Runs in 6-month chunks so progress is logged incrementally.
+    Open-Meteo has data from 1940-01-01 to present.
+    """
+    from jobs.weather_sync import run_weather_backfill
+
+    background_tasks.add_task(
+        run_weather_backfill,
+        from_date=from_date,
+        to_date=to_date,
+        triggered_by=f"user:{current_user['username']}"
+    )
+
+    return {
+        "status": "started",
+        "source": "open_meteo",
+        "from_date": from_date,
+        "to_date": to_date,
+        "message": f"Weather backfill {from_date} to {to_date} started in background"
+    }
+
+
+@router.get("/weather/status")
+async def get_weather_status(
+    db: AsyncSession = Depends(get_db),
+    current_user: dict = Depends(get_current_user)
+):
+    """Return weather data coverage and last sync status."""
+    coverage = await db.execute(text("""
+        SELECT
+            MIN(date) as first_date,
+            MAX(date) as last_date,
+            COUNT(*) as total_days
+        FROM weather_data
+    """))
+    cov = coverage.fetchone()
+
+    last_sync = await db.execute(text("""
+        SELECT completed_at, status, records_fetched, records_created, date_from, date_to
+        FROM sync_log
+        WHERE source = 'open_meteo'
+        ORDER BY started_at DESC LIMIT 1
+    """))
+    sync_row = last_sync.fetchone()
+
+    return {
+        "coverage": {
+            "first_date": cov.first_date,
+            "last_date": cov.last_date,
+            "total_days": cov.total_days,
+        },
+        "last_sync": {
+            "completed_at": sync_row.completed_at if sync_row else None,
+            "status": sync_row.status if sync_row else None,
+            "records_fetched": sync_row.records_fetched if sync_row else None,
+            "date_from": sync_row.date_from if sync_row else None,
+            "date_to": sync_row.date_to if sync_row else None,
+        }
+    }