Fix PWA install hint dismiss after cached HTML/JS mismatch.

Restore button id, bind dismiss at document level, force hide inline, and fetch pwa.js/style.css network-first.

Co-authored-by: Cursor <cursoragent@cursor.com>

templates/_pwa_head.html

@@ -3,4 +3,4 @@
 <meta name="apple-mobile-web-app-capable" content="yes">
 <meta name="apple-mobile-web-app-status-bar-style" content="black-translucent">
 <link rel="apple-touch-icon" href="/static/icon-192.png">
-<script src="/static/pwa.js" defer></script>
+<script src="/static/pwa.js?v=7" defer></script>

templates/_pwa_hint.html

@@ -5,6 +5,6 @@
   </div>
   <div class="pwa-hint-actions">
     <button type="button" id="pwa-install-btn" class="viewer-copy-btn" hidden data-i18n="pwa.install">Install</button>
-    <button type="button" class="pwa-hint-dismiss" aria-label="Dismiss">×</button>
+    <button type="button" id="pwa-hint-dismiss" class="pwa-hint-dismiss" aria-label="Dismiss">×</button>
   </div>
 </div>