feat(desktop): auto-recover in-progress desktop tasks on client lifecycle events

- reset stale in_progress tasks owned by a client on startup, offline, and lease expiry
- monitor tasks re-queue for another pick; publish tasks move to unknown for manual reconcile
- send startup=true flag on first heartbeat so the server can trigger recovery
- finalize the linked desktop task when a phase2 monitor callback arrives via desktop_tasks path
- short-circuit the desktop monitor attempt write after the callback already finalized it

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

server/internal/tenant/app/desktop_client_service.go

@@ -21,14 +21,20 @@ import (
 const DesktopClientTokenTTL = 30 * 24 * time.Hour
 
 type DesktopClientService struct {
-	repo  repository.DesktopClientRepository
-	redis *goredis.Client
+	repo    repository.DesktopClientRepository
+	redis   *goredis.Client
+	taskSvc *DesktopTaskService
 }
 
 func NewDesktopClientService(repo repository.DesktopClientRepository, redis *goredis.Client) *DesktopClientService {
 	return &DesktopClientService{repo: repo, redis: redis}
 }
 
+func (s *DesktopClientService) WithTaskService(taskSvc *DesktopTaskService) *DesktopClientService {
+	s.taskSvc = taskSvc
+	return s
+}
+
 type RegisterDesktopClientRequest struct {
 	ClientID      string `json:"client_id"`
 	DeviceName    string `json:"device_name" binding:"required"`
@@ -45,6 +51,7 @@ type HeartbeatDesktopClientRequest struct {
 	ClientVersion *string  `json:"client_version"`
 	Channel       *string  `json:"channel"`
 	AccountIDs    []string `json:"account_ids"`
+	Startup       bool     `json:"startup"`
 }
 
 type DesktopClientView struct {
@@ -182,6 +189,12 @@ func (s *DesktopClientService) Heartbeat(ctx context.Context, client *repository
 	markDesktopClientPresent(ctx, s.redis, updated.ID)
 	markDesktopAccountsPresent(ctx, s.redis, updated.ID, parseDesktopAccountIDs(req.AccountIDs))
 
+	if req.Startup && s.taskSvc != nil {
+		if err := s.taskSvc.recoverClientTasksOnStartup(ctx, updated); err != nil {
+			return nil, err
+		}
+	}
+
 	return &HeartbeatDesktopClientResponse{
 		Client:     buildDesktopClientView(updated),
 		ServerTime: time.Now().UTC(),
@@ -202,6 +215,11 @@ func (s *DesktopClientService) Revoke(ctx context.Context, client *repository.De
 	}
 
 	clearDesktopClientPresenceState(ctx, s.redis, updated.ID)
+	if s.taskSvc != nil {
+		if err := s.taskSvc.recoverClientTasksOnDisconnect(ctx, updated); err != nil {
+			return nil, err
+		}
+	}
 
 	view := buildDesktopClientView(updated)
 	return &view, nil
@@ -213,6 +231,11 @@ func (s *DesktopClientService) Offline(ctx context.Context, client *repository.D
 	}
 
 	clearDesktopClientPresenceState(ctx, s.redis, client.ID)
+	if s.taskSvc != nil {
+		if err := s.taskSvc.recoverClientTasksOnDisconnect(ctx, client); err != nil {
+			return nil, err
+		}
+	}
 
 	return &OfflineDesktopClientResponse{
 		ServerTime: time.Now().UTC(),