feat(server): implement chat file TTL cleanup and enhance JPush vendor channel support

Add FileCleanupWorker for automatic expiration of chat files with configurable retention period and batch processing. Files uploaded via `/api/v1/uploads/files` are tracked in `uploaded_files` table with expiration timestamps, then deleted from S3 and database upon expiry. Expired file URLs are injected as `"expired": true` in message responses.

Extend JPush push notification configuration with vendor-specific channel_id support (xiaomi, huawei, oppo, vivo, meizu, honor, fcm) for differentiating system vs chat notifications. Add iOS APNs thread-id grouping configuration for notification categorization.

internal/pkg/jpush/vendor/text_renderer.go

@@ -0,0 +1,61 @@
+package vendor
+
+import (
+	"with_you/internal/config"
+	"with_you/internal/pkg/jpush"
+)
+
+// defaultRenderer 默认通用文本渲染器
+type defaultRenderer struct{}
+
+func newDefaultRenderer() *defaultRenderer {
+	return &defaultRenderer{}
+}
+
+// mergeExtras 合并基础 extras 与额外 extras，返回新 map
+func mergeExtras(messageType string, extra map[string]any) map[string]any {
+	out := make(map[string]any, len(extra)+1)
+	if messageType != "" {
+		out["notification_type"] = messageType
+	}
+	for k, v := range extra {
+		out[k] = v
+	}
+	return out
+}
+
+// RenderAndroid 渲染 Android 通用通知
+// 所有 Android 厂商共享：alert/title/channel_id/extras/large_icon/priority
+func (r *defaultRenderer) RenderAndroid(params MessageParams, cfg config.ChannelConfig) *jpush.AndroidNotif {
+	channelID := cfg.Chat
+	if params.Scene == SceneSystem {
+		channelID = cfg.System
+	}
+	return &jpush.AndroidNotif{
+		Alert:     params.Body,
+		Title:     params.Title,
+		ChannelID: channelID,
+		LargeIcon: params.LargeIcon,
+		Extras:    mergeExtras(params.MessageType, params.Extra),
+		Priority:  1,
+	}
+}
+
+// RenderIOS 渲染 iOS 通用通知
+// iOS 走 APNs，通过 thread-id 实现按场景的通知分组
+func (r *defaultRenderer) RenderIOS(params MessageParams, cfg config.ChannelConfig) *jpush.IOSNotif {
+	threadID := cfg.IOS.ChatThreadID
+	if params.Scene == SceneSystem {
+		threadID = cfg.IOS.SystemThreadID
+	}
+	return &jpush.IOSNotif{
+		Alert: map[string]any{
+			"title": params.Title,
+			"body":  params.Body,
+		},
+		Sound:    "default",
+		Badge:    "+1",
+		ThreadID: threadID,
+		Extras:   mergeExtras(params.MessageType, params.Extra),
+	}
+}