fix: 工单列表权限过滤-developer/auditor也能看到待审工单

- developer之前只能看applicant_id=自己的工单，导致审批人看不到待审工单
- 改为admin看全部，其他角色(包括developer/dba/auditor)都能看到自己提交+自己作为审批人的工单
- E2E全流程验证通过: testtest提交→test123初审→test234复审→admin执行→success

backend/internal/handler/ticket.go

@@ -84,9 +84,9 @@ func ListTickets(c *gin.Context) {
 	
 	// Filter by user role
 	switch role {
-	case "developer":
-		query = query.Where("applicant_id = ?", userID)
-	case "dba", "auditor":
+	case "admin":
+		// admin sees all tickets
+	default:
 		query = query.Where(
 			"applicant_id = ? OR id IN (SELECT ticket_id FROM ticket_approvals WHERE approver_id = ?)",
 			userID, userID,