fix(deploy): 看门狗飞书告警中文乱码改 UTF-8 发送

PS5 Invoke-RestMethod 对字符串 body 默认按 Latin-1 编码导致中文变 ???，
改为手动转 UTF-8 字节数组并声明 charset=utf-8。

deploy/watchdog.ps1

@@ -25,12 +25,15 @@ function Write-Log($msg) {
 
 function Send-Alert($title, $msg) {
     if (-not $FeishuWebhook) { return }
-    $body = @{
+    $json = @{
         msg_type = "text"
         content  = @{ text = "[$title] $msg" }
     } | ConvertTo-Json -Depth 3
     try {
-        Invoke-RestMethod -Uri $FeishuWebhook -Method Post -Body $body -ContentType "application/json" -TimeoutSec 10
+        # PS5 的 Invoke-RestMethod 对字符串 body 默认按 Latin-1 编码，中文会变成 ???，
+        # 必须手动转 UTF-8 字节数组发送
+        $bytes = [System.Text.Encoding]::UTF8.GetBytes($json)
+        Invoke-RestMethod -Uri $FeishuWebhook -Method Post -Body $bytes -ContentType "application/json; charset=utf-8" -TimeoutSec 10
     } catch {
         Write-Log "飞书告警发送失败: $_"
     }