fix(team_process): Clean up stuck processing owners on startup and batch completion

- Add CleanupStuckProcessingOwners database method to reset owners stuck in processing status back to valid state
- Call cleanup routine on application startup to recover from previous abnormal exits
- Call cleanup routine after batch processing completes to ensure no orphaned processing states remain
- Add markOwnerResult calls in processSingleTeam when team invitations are full to properly track owner status
- Prevents owners from being permanently stuck in processing state due to unexpected shutdowns or errors

backend/internal/database/sqlite.go

@@ -627,6 +627,15 @@ func (d *DB) CleanupStuckBatchRuns() (int64, error) {
 	return result.RowsAffected()
 }
 
+// CleanupStuckProcessingOwners 清理卡住的 processing 状态母号，重置为 valid
+func (d *DB) CleanupStuckProcessingOwners() (int64, error) {
+	result, err := d.db.Exec(`UPDATE team_owners SET status = 'valid' WHERE status = 'processing'`)
+	if err != nil {
+		return 0, err
+	}
+	return result.RowsAffected()
+}
+
 // GetBatchRunStats 获取批次统计
 func (d *DB) GetBatchRunStats() map[string]interface{} {
 	stats := make(map[string]interface{})