hub: scan recorded_at via sql.NullTime in ListCameras

modernc/sqlite returns a COALESCE() expression as a raw string (no column
type affinity), which can't scan into *time.Time. Drop the COALESCE on the
timestamp and scan the plain DATETIME column (which modernc returns as
time.Time) through sql.NullTime, so a camera with no status row yet lists
with a zero time instead of erroring out the whole list.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

internal/api/cameras.go

@@ -31,7 +31,7 @@ func ListCameras(database *db.DB) http.HandlerFunc {
 				s.resolution,
 				s.fps,
 				COALESCE(s.online, 0),
-				COALESCE(s.recorded_at, c.created_at)
+				s.recorded_at
 			FROM cameras c
 			LEFT JOIN (
 				SELECT camera_id, battery_pct, video_remaining_sec, recording_state,
@@ -52,15 +52,17 @@ func ListCameras(database *db.DB) http.HandlerFunc {
 		for rows.Next() {
 			var sl models.StatusLog
 			var c models.Camera
+			var recordedAt sql.NullTime // NULL for a camera with no status yet
 			if err := rows.Scan(
 				&c.CameraID, &c.FriendlyName,
 				&sl.BatteryPct, &sl.VideoRemainingSec,
 				&sl.RecordingState, &sl.Mode, &sl.Resolution, &sl.FPS,
-				&sl.Online, &sl.RecordedAt,
+				&sl.Online, &recordedAt,
 			); err != nil {
 				log.Printf("Error scanning camera row: %v", err)
 				continue
 			}
+			sl.RecordedAt = recordedAt.Time // zero time if no status
 			statuses = append(statuses, models.NewCameraStatus(c, sl))
 		}
 		if err := rows.Err(); err != nil {