fix: bugcollect V4 拆分为 V4+V5，解决 MySQL 不兼容 ADD COLUMN IF NOT EXISTS 问题

V4: CREATE TABLE IF NOT EXISTS（全部幂等）
V5: ALTER TABLE ADD COLUMN + CREATE INDEX（升级场景需手动处理）

xuqm-bugcollect-service/src/main/resources/db/migration/V4__bugcollect_v12.sql

@@ -1,7 +1,9 @@
 -- V4: log_issue_users dedup table, secret on log_webhooks, log_sessions skeleton
 -- ──────────────────────────────────────────────────────────────────────────────
+-- MySQL 兼容：不使用 ADD COLUMN IF NOT EXISTS / ADD INDEX IF NOT EXISTS
+-- 全新部署时顺序执行无问题；升级场景若部分执行过，需手动修复 flyway_history_log
 
--- Dedup table for affectedUsers counting (one row per issue × user)
+-- 1) Dedup table for affectedUsers counting (one row per issue × user)
 CREATE TABLE IF NOT EXISTS log_issue_users (
     issue_id    BIGINT       NOT NULL,
     user_id     VARCHAR(128) NOT NULL,
@@ -10,14 +12,7 @@ CREATE TABLE IF NOT EXISTS log_issue_users (
     INDEX idx_liu_issue_id (issue_id)
 ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;
 
--- HMAC signing secret for webhooks (nullable = no signing)
--- MySQL does not support ADD COLUMN IF NOT EXISTS.
--- If the column already exists (e.g. partial re-run), this migration will fail.
--- V5__bugcollect_v12_repair.sql handles the repair case.
-ALTER TABLE log_webhooks
-    ADD COLUMN secret VARCHAR(64) NULL COMMENT 'HMAC-SHA256 signing secret; NULL = no signature';
-
--- Session tracking table (ingestion path via /sessions/batch is not yet implemented)
+-- 2) Session tracking table (ingestion path via /sessions/batch is not yet implemented)
 CREATE TABLE IF NOT EXISTS log_sessions (
     id           BIGINT       NOT NULL AUTO_INCREMENT,
     app_key      VARCHAR(64)  NOT NULL,
@@ -36,6 +31,3 @@ CREATE TABLE IF NOT EXISTS log_sessions (
     INDEX idx_ls_app_key (app_key),
     INDEX idx_ls_started_at (started_at)
 ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;
-
--- Ensure event_id has an index (was added as NULL in V3)
-CREATE INDEX idx_lie_event_id ON log_issue_events (event_id);

xuqm-bugcollect-service/src/main/resources/db/migration/V5__bugcollect_v12_part2.sql

@@ -0,0 +1,18 @@
+-- V5: bugcollect v12 part 2 — ALTER TABLE / CREATE INDEX
+-- ─────────────────────────────────────────────────────────
+-- 分离到 V5 是因为 MySQL 不支持 ADD COLUMN IF NOT EXISTS / ADD INDEX IF NOT EXISTS。
+-- 全新部署：V4 + V5 顺序执行，全部成功。
+-- 升级场景：若 V4 部分执行过（secret 列已存在），需手动修复：
+--   1) docker exec mysql mysql -uxuqm -p'...' xuqm_bugcollect
+--      DELETE FROM flyway_history_log WHERE version IN (4,5);
+--      ALTER TABLE log_webhooks ADD COLUMN IF NOT EXISTS secret VARCHAR(64) NULL;
+--      CREATE INDEX IF NOT EXISTS idx_lie_event_id ON log_issue_events (event_id);
+--      INSERT INTO flyway_history_log (...) VALUES (4, ...), (5, ...);
+--   2) docker restart bugcollect-service
+
+-- HMAC signing secret for webhooks (nullable = no signing)
+ALTER TABLE log_webhooks
+    ADD COLUMN secret VARCHAR(64) NULL COMMENT 'HMAC-SHA256 signing secret; NULL = no signature';
+
+-- Ensure event_id has an index (was added as NULL in V3)
+CREATE INDEX idx_lie_event_id ON log_issue_events (event_id);