fix(db): 日志与忽略记录时间统一为北京时间（东八区墙上时间）

- SQLite DEFAULT CURRENT_TIMESTAMP 为 UTC，与前端展示差 8 小时
- 新增 nowIso() 显式写入东八区墙上时间（YYYY-MM-DD HH:MM:SS）
- 旧数据迁移 v1：日志/忽略记录 UTC 时间统一转北京时间，settings 标志位防重复执行
- 已用临时库验证迁移、幂等与新写入格式

backend/db.js

@@ -35,12 +35,52 @@ CREATE TABLE IF NOT EXISTS logs (
 );
 `)
 
+// 北京时间（Asia/Shanghai 固定 UTC+8，无夏令时）：SQLite DEFAULT CURRENT_TIMESTAMP 是 UTC，
+// 与前端按本地时间展示相差 8 小时，故写入与迁移统一显式使用北京时间墙上时间字符串
+// （格式与前端 slice 兼容：YYYY-MM-DD HH:MM:SS，不带时区后缀，避免被二次误解）
+const pad2 = n => String(n).padStart(2, '0')
+export function nowIso() {
+  const d = new Date(Date.now() + 8 * 3600_000)
+  return `${d.getUTCFullYear()}-${pad2(d.getUTCMonth() + 1)}-${pad2(d.getUTCDate())} ${pad2(d.getUTCHours())}:${pad2(d.getUTCMinutes())}:${pad2(d.getUTCSeconds())}`
+}
+
+function utcToShanghai(iso) {
+  try {
+    const ts = Date.parse(iso)
+    if (!Number.isFinite(ts)) return null
+    const d = new Date(ts + 8 * 3600_000)
+    return `${d.getUTCFullYear()}-${pad2(d.getUTCMonth() + 1)}-${pad2(d.getUTCDate())} ${pad2(d.getUTCHours())}:${pad2(d.getUTCMinutes())}:${pad2(d.getUTCSeconds())}`
+  } catch {
+    return null
+  }
+}
+
 // 旧库迁移：早期 logs 表无 action 列，运行时补齐（忽略/取消忽略等操作依赖该列区分类型）
 const logCols = db.prepare('PRAGMA table_info(logs)').all().map(c => c.name)
 if (!logCols.includes('action')) {
   db.exec("ALTER TABLE logs ADD COLUMN action TEXT DEFAULT 'clean'")
 }
 
+// 旧库迁移 v1：历史日志/忽略记录的时间戳是 UTC，统一转成北京时间；settings 标志位防重复执行
+function migrateTimezone() {
+  if (getSetting('timezone_migrated_v1')) return
+  db.transaction(() => {
+    for (const { id, created_at: t } of db.prepare('SELECT id, created_at FROM logs').all()) {
+      if (t) {
+        const local = utcToShanghai(t)
+        if (local) db.prepare('UPDATE logs SET created_at = ? WHERE id = ?').run(local, id)
+      }
+    }
+    for (const { pkg_name: n, ignored_at: t } of db.prepare('SELECT pkg_name, ignored_at FROM ignored_packages').all()) {
+      if (t) {
+        const local = utcToShanghai(t)
+        if (local) db.prepare('UPDATE ignored_packages SET ignored_at = ? WHERE pkg_name = ?').run(local, n)
+      }
+    }
+    setSetting('timezone_migrated_v1', '1')
+  })()
+}
+
 // —— settings ——
 export function getSetting(key, def = null) {
   const row = db.prepare('SELECT value FROM settings WHERE key = ?').get(key)
@@ -68,8 +108,8 @@ export function isIgnored(pkgName) {
 
 export function addIgnored(pkgName) {
   db.prepare(
-    'INSERT INTO ignored_packages (pkg_name) VALUES (?) ON CONFLICT(pkg_name) DO NOTHING',
-  ).run(pkgName)
+    'INSERT INTO ignored_packages (pkg_name, ignored_at) VALUES (?, ?) ON CONFLICT(pkg_name) DO NOTHING',
+  ).run(pkgName, nowIso())
 }
 
 export function removeIgnored(pkgName) {
@@ -79,8 +119,8 @@ export function removeIgnored(pkgName) {
 // —— logs ——
 export function addLog({ action = 'clean', pkgName, deletedVersions = null, deletedCount = 0, freedSpace = null }) {
   const info = db.prepare(
-    'INSERT INTO logs (action, pkg_name, deleted_versions, deleted_count, freed_space) VALUES (?, ?, ?, ?, ?)',
-  ).run(action, pkgName, deletedVersions, deletedCount, freedSpace)
+    'INSERT INTO logs (action, pkg_name, deleted_versions, deleted_count, freed_space, created_at) VALUES (?, ?, ?, ?, ?, ?)',
+  ).run(action, pkgName, deletedVersions, deletedCount, freedSpace, nowIso())
   return info.lastInsertRowid
 }
 
@@ -90,4 +130,7 @@ export function getLogs(limit = 50) {
   ).all(limit)
 }
 
+// 模块加载时执行时间迁移（幂等）
+migrateTimezone()
+
 export default db