fix(logs): 忽略/取消忽略操作写入操作日志

原 /api/ignore 与 /api/ignore/:pkgName 只写 ignored_packages 表不记日志，
导致操作日志页查不到忽略记录。logs 表新增 action 列区分操作类型
(clean/ignore/unignore，旧库运行时 ALTER TABLE 迁移)，忽略与取消忽略
接口补写 addLog；日志页按操作类型展示徽标与详情，删除数量/释放空间对
非清理操作显示占位符。

backend/db.js

@@ -26,6 +26,7 @@ CREATE TABLE IF NOT EXISTS ignored_packages (
 );
 CREATE TABLE IF NOT EXISTS logs (
   id               INTEGER PRIMARY KEY AUTOINCREMENT,
+  action           TEXT DEFAULT 'clean',
   pkg_name         TEXT,
   deleted_versions TEXT,
   deleted_count    INTEGER,
@@ -34,6 +35,12 @@ CREATE TABLE IF NOT EXISTS logs (
 );
 `)
 
+// 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'")
+}
+
 // —— settings ——
 export function getSetting(key, def = null) {
   const row = db.prepare('SELECT value FROM settings WHERE key = ?').get(key)
@@ -70,10 +77,10 @@ export function removeIgnored(pkgName) {
 }
 
 // —— logs ——
-export function addLog({ pkgName, deletedVersions, deletedCount, freedSpace }) {
+export function addLog({ action = 'clean', pkgName, deletedVersions = null, deletedCount = 0, freedSpace = null }) {
   const info = db.prepare(
-    'INSERT INTO logs (pkg_name, deleted_versions, deleted_count, freed_space) VALUES (?, ?, ?, ?)',
-  ).run(pkgName, deletedVersions, deletedCount, freedSpace)
+    'INSERT INTO logs (action, pkg_name, deleted_versions, deleted_count, freed_space) VALUES (?, ?, ?, ?, ?)',
+  ).run(action, pkgName, deletedVersions, deletedCount, freedSpace)
   return info.lastInsertRowid
 }