fix(aihr): harden legacy schema migrations

backend/script/sql/update/aihr_20260714_org_hire_date_mysql8.sql

@@ -1,5 +1,18 @@
 -- AIHR 组织快照入职日期迁移（MySQL 8.x）
 -- 仅补齐结构，不写入业务数据；可重复执行。
+SET @aihr_org_snapshot_table_exists := (
+  SELECT COUNT(*)
+  FROM information_schema.TABLES
+  WHERE TABLE_SCHEMA = DATABASE()
+    AND TABLE_NAME = 'aihr_org_snapshot'
+);
+SET @aihr_employment_status_exists := (
+  SELECT COUNT(*)
+  FROM information_schema.COLUMNS
+  WHERE TABLE_SCHEMA = DATABASE()
+    AND TABLE_NAME = 'aihr_org_snapshot'
+    AND COLUMN_NAME = 'employment_status'
+);
 SET @aihr_hire_date_exists := (
   SELECT COUNT(*)
   FROM information_schema.COLUMNS
@@ -8,8 +21,12 @@ SET @aihr_hire_date_exists := (
     AND COLUMN_NAME = 'hire_date'
 );
 SET @aihr_hire_date_ddl := IF(
-  @aihr_hire_date_exists = 0,
-  'ALTER TABLE aihr_org_snapshot ADD COLUMN `hire_date` date DEFAULT NULL COMMENT ''入职日期（用于新员工三个月资格判断）'' AFTER `employment_status`',
+  @aihr_org_snapshot_table_exists = 1 AND @aihr_hire_date_exists = 0,
+  IF(
+    @aihr_employment_status_exists = 1,
+    'ALTER TABLE aihr_org_snapshot ADD COLUMN `hire_date` date DEFAULT NULL COMMENT ''入职日期（用于新员工三个月资格判断）'' AFTER `employment_status`',
+    'ALTER TABLE aihr_org_snapshot ADD COLUMN `hire_date` date DEFAULT NULL COMMENT ''入职日期（用于新员工三个月资格判断）'''
+  ),
   'SELECT 1'
 );
 PREPARE aihr_hire_date_stmt FROM @aihr_hire_date_ddl;

backend/script/sql/update/aihr_20260714_sop_requester_identity_mysql8.sql

@@ -7,6 +7,22 @@ SET @aihr_sop_review_table_exists := (
   WHERE TABLE_SCHEMA = DATABASE()
     AND TABLE_NAME = 'aihr_sop_answer_review'
 );
+SET @aihr_sop_source_exists := (
+  SELECT COUNT(*)
+  FROM information_schema.COLUMNS
+  WHERE TABLE_SCHEMA = DATABASE()
+    AND TABLE_NAME = 'aihr_sop_answer_review'
+    AND COLUMN_NAME = 'source'
+);
+SET @aihr_sop_source_ddl := IF(
+  @aihr_sop_review_table_exists = 1 AND @aihr_sop_source_exists = 0,
+  'ALTER TABLE aihr_sop_answer_review ADD COLUMN `source` varchar(50) DEFAULT ''knowledge_search'' COMMENT ''来源''',
+  'SELECT 1'
+);
+PREPARE aihr_sop_source_stmt FROM @aihr_sop_source_ddl;
+EXECUTE aihr_sop_source_stmt;
+DEALLOCATE PREPARE aihr_sop_source_stmt;
+
 SET @aihr_sop_requester_exists := (
   SELECT COUNT(*)
   FROM information_schema.COLUMNS
@@ -16,7 +32,7 @@ SET @aihr_sop_requester_exists := (
 );
 SET @aihr_sop_requester_ddl := IF(
   @aihr_sop_review_table_exists = 1 AND @aihr_sop_requester_exists = 0,
-  'ALTER TABLE aihr_sop_answer_review ADD COLUMN `requester_ext_party_id` varchar(100) DEFAULT NULL COMMENT ''提问员工外部主体ID'' AFTER `source`',
+  'ALTER TABLE aihr_sop_answer_review ADD COLUMN `requester_ext_party_id` varchar(100) DEFAULT NULL COMMENT ''提问员工外部主体ID''',
   'SELECT 1'
 );
 PREPARE aihr_sop_requester_stmt FROM @aihr_sop_requester_ddl;