v0.3.5: restore full push notification system (14 channels)

Restored from v0.2.4:
- notifiers/: 14 push channels (bark/serverchan/telegram/lark/webhook/wechat/discord/smtp/...)
- push-user.service.ts: multi-user push config linked to cloud_configs.promotion_account
- notification.service.ts: full dispatcher with per-config + global fallback

New integrations:
- cloud.service.ts: notifyConfigEvent on save_success/cookie_expire/save_fail
- admin.routes.ts: 7 new API endpoints for push users, notify providers, channel test
- database.ts: migration for cloud_configs.notify_config column

How it works:
- Configure push channels in /admin/system-configs (global_notify_config JSON)
- Or per-cloud: link push_users.account = cloud_configs.promotion_account
- Notify events: save_success (green), cookie_expire (red), save_fail >=3 consecutive (yellow)

source_clean/src/cloud/notifiers/serverchanturbo.notifier.ts

@@ -0,0 +1,29 @@
+import { Notifier, NotifyParams, NotifyResult, NotifierParam } from './notifier.types';
+
+const params: NotifierParam[] = [
+{ key: 'sendkey', label: 'SendKey', type: 'password', required: true, placeholder: 'Server酱 Turbo SendKey' },
+    { key: 'title', label: '标题', type: 'text', default: 'CloudSearch', required: false },
+    { key: 'content', label: '内容', type: 'text', required: true },
+];
+
+export const serverchanturboNotifier: Notifier = {
+name: 'serverchanturbo',
+    label: 'Server酱 Turbo',
+    params,
+    async notify(params) {
+        try {
+            const resp = await fetch(`https://sctapi.ftqq.com/${params.sendkey}.send`, {
+                method: 'POST',
+                headers: { 'Content-Type': 'application/x-www-form-urlencoded' },
+                body: new URLSearchParams({ title: params.title || 'CloudSearch', desp: params.content || '' }).toString(),
+            });
+            const data: any = await resp.json();
+            if (data.code === 0)
+                return { success: true, message: 'Server酱 Turbo 推送成功' };
+            return { success: false, message: data.message || `HTTP ${resp.status}` };
+        }
+        catch (err: any) {
+            return { success: false, message: err.message };
+        }
+    },
+};