fix(daemon): convert cc_info timestamps to UTC before sending to server

The cc_info fetching was sending timestamps with local timezone offset
(e.g., "2026-01-04T00:00:00+08:00"), but the server stores data in UTC.
If the server doesn't properly parse the timezone offset, it causes a
mismatch in the returned data.

Now timestamps are converted to UTC before formatting, ensuring the
server receives unambiguous UTC values while still respecting the
user's local timezone for day/week/month boundaries.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: AnnatarHe

daemon/cc_info_timer.go

@@ -217,10 +217,14 @@ func (s *CCInfoTimerService) fetchCost(ctx context.Context, timeRange CCInfoTime
 		since = time.Date(now.Year(), now.Month(), now.Day(), 0, 0, 0, 0, now.Location())
 	}
 
+	// Convert to UTC before sending to server to avoid timezone parsing issues
+	sinceUTC := since.UTC()
+	nowUTC := now.UTC()
+
 	variables := map[string]interface{}{
 		"filter": map[string]interface{}{
-			"since":      since.Format(time.RFC3339),
-			"until":      now.Format(time.RFC3339),
+			"since":      sinceUTC.Format(time.RFC3339),
+			"until":      nowUTC.Format(time.RFC3339),
 			"clientType": "claude_code",
 		},
 	}

model/cc_statusline_service.go

@@ -55,10 +55,14 @@ func FetchDailyCost(ctx context.Context, config ShellTimeConfig) (float64, error
 	now := time.Now()
 	startOfDay := time.Date(now.Year(), now.Month(), now.Day(), 0, 0, 0, 0, now.Location())
 
+	// Convert to UTC before sending to server to avoid timezone parsing issues
+	startOfDayUTC := startOfDay.UTC()
+	nowUTC := now.UTC()
+
 	variables := map[string]interface{}{
 		"filter": map[string]interface{}{
-			"since":      startOfDay.Format(time.RFC3339),
-			"until":      now.Format(time.RFC3339),
+			"since":      startOfDayUTC.Format(time.RFC3339),
+			"until":      nowUTC.Format(time.RFC3339),
 			"clientType": "claude_code",
 		},
 	}