feat: update vps-panel backup and notification features

src/lib/ping.ts

@@ -1,5 +1,6 @@
 import { Site } from './config'
-import { insertPingLog } from './appDb'
+import { insertPingLog, getLastLog } from './appDb'
+import { sendStatusAlert } from './notify'
 
 export async function pingSite(site: Site): Promise<{
   status: 'up' | 'down' | 'degraded'
@@ -29,7 +30,14 @@ export async function pingSite(site: Site): Promise<{
 }
 
 export async function pingAndLog(site: Site) {
+  const previous = await getLastLog(site.id)
   const result = await pingSite(site)
   await insertPingLog({ site_id: site.id, ...result })
+
+  // Durum değişti mi? → bildirim gönder
+  if (previous && previous.status !== result.status) {
+    sendStatusAlert(site.name, site.url, previous.status, result.status, result.ms).catch(() => {})
+  }
+
   return result
 }