Add UI editing for local DNS zones

Local zones were only editable as mounted files, so operators could not manage DNS entries from the console. Add a Local zones editor backed by a shared Kubernetes ConfigMap, validate master files before saving, scope the pod service account to that ConfigMap, and reload changed zones on every replica while flushing stale cache entries.

internal/web/dist/index.html

@@ -5,8 +5,8 @@
     <link rel="icon" type="image/svg+xml" href="/favicon.svg" />
     <meta name="viewport" content="width=device-width, initial-scale=1.0" />
     <title>web</title>
-    <script type="module" crossorigin src="/assets/index-D_F84V7q.js"></script>
-    <link rel="stylesheet" crossorigin href="/assets/index-CZ8p4VMZ.css">
+    <script type="module" crossorigin src="/assets/index-B-5PHdii.js"></script>
+    <link rel="stylesheet" crossorigin href="/assets/index-YXlSytfO.css">
   </head>
   <body>
     <div id="root"></div>