fix: remove Topic header, add push response logging

- Remove Topic header (causes issues with Apple push service)
- Log push response status codes for debugging
- Log endpoint prefix on errors for identification
- Auto-cleanup 410 (gone) subscriptions on success path too

internal/push/handlers.go

@@ -169,17 +169,20 @@ func (h *Handler) SendPush(ctx context.Context, userID string, payload map[strin
 			VAPIDPrivateKey: h.vapidPriv,
 			TTL:             86400,
 			Urgency:         webpush.UrgencyHigh,
-			Topic:           userID,
 		})
 		if err != nil {
-			h.logger.Error("failed to send push", "error", err, "user_id", userID)
+			h.logger.Error("failed to send push", "error", err, "user_id", userID, "endpoint", endpoint[:min(60, len(endpoint))])
 			if resp != nil && resp.StatusCode == 410 {
 				h.db.ExecContext(ctx, `DELETE FROM push_subscriptions WHERE endpoint = $1`, endpoint)
 			}
 			continue
 		}
 		if resp != nil {
+			h.logger.Info("push sent", "user_id", userID, "status", resp.StatusCode, "endpoint", endpoint[:min(60, len(endpoint))])
 			resp.Body.Close()
+			if resp.StatusCode == 410 {
+				h.db.ExecContext(ctx, `DELETE FROM push_subscriptions WHERE endpoint = $1`, endpoint)
+			}
 		}
 	}
 }
@@ -246,7 +249,6 @@ func (h *Handler) SendChannelNotification(ctx context.Context, channelID, author
 			VAPIDPrivateKey: h.vapidPriv,
 			TTL:             86400,
 			Urgency:         webpush.UrgencyHigh,
-			Topic:           userID,
 		})
 		if err != nil {
 			h.logger.Error("failed to send push", "error", err, "user_id", userID)