fix(model-manager): replace window.confirm with in-app modal

Browsers suppress native confirm() dialogs after repeated use (the
"prevent this page from creating additional dialogs" checkbox), which
silently broke deletes. Add a promise-based in-app confirmation modal
and use it for gallery photo and installed-model deletes.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

model-manager/app/static/app.js

@@ -32,6 +32,33 @@ function fmtDate(epoch) {
   return new Date(epoch * 1000).toLocaleString();
 }
 
+// In-app confirmation dialog (replaces window.confirm, which browsers can
+// suppress after repeated use). Returns a Promise<boolean>.
+function confirmDialog(message, okLabel = "Delete") {
+  return new Promise((resolve) => {
+    const overlay = $("#confirmModal");
+    $("#confirmMsg").textContent = message;
+    $("#confirmOk").textContent = okLabel;
+    overlay.hidden = false;
+    const done = (val) => {
+      overlay.hidden = true;
+      $("#confirmOk").onclick = null;
+      $("#confirmCancel").onclick = null;
+      overlay.onclick = null;
+      document.removeEventListener("keydown", onKey);
+      resolve(val);
+    };
+    function onKey(e) {
+      if (e.key === "Escape") done(false);
+      if (e.key === "Enter") done(true);
+    }
+    $("#confirmOk").onclick = () => done(true);
+    $("#confirmCancel").onclick = () => done(false);
+    overlay.onclick = (e) => { if (e.target === overlay) done(false); };
+    document.addEventListener("keydown", onKey);
+  });
+}
+
 // ---- navigation -----------------------------------------------------------
 
 function showView(name) {
@@ -118,7 +145,7 @@ function renderModels(models) {
 }
 
 async function deleteModel(m) {
-  if (!confirm(`Delete ${m.name}?`)) return;
+  if (!(await confirmDialog(`Delete ${m.name}?`))) return;
   try {
     await api("/api/models", {
       method: "DELETE",
@@ -307,7 +334,7 @@ function renderPhotoCard(p) {
 }
 
 async function deletePhoto(p, card) {
-  if (!confirm(`Permanently delete ${p.name}?`)) return;
+  if (!(await confirmDialog(`Permanently delete ${p.name}?`))) return;
   try {
     await api("/api/gallery", {
       method: "DELETE",

model-manager/app/static/index.html

@@ -194,6 +194,17 @@
     </div>
   </div>
 
+  <!-- In-app confirmation dialog (replaces native window.confirm) -->
+  <div id="confirmModal" class="modal-overlay" hidden>
+    <div class="modal">
+      <p id="confirmMsg"></p>
+      <div class="modal-actions">
+        <button class="btn" id="confirmCancel">Cancel</button>
+        <button class="btn danger-solid" id="confirmOk">Delete</button>
+      </div>
+    </div>
+  </div>
+
   <script src="/app.js"></script>
 </body>
 </html>

model-manager/app/static/style.css

@@ -172,6 +172,23 @@ code { background: var(--bg-3); padding: 1px 5px; border-radius: 4px; font-size:
   .nav-ico { font-size: 18px; }
 }
 
+/* ---- confirm modal ---- */
+.modal-overlay {
+  position: fixed; inset: 0; z-index: 200;
+  background: rgba(8,10,16,.7);
+  display: flex; align-items: center; justify-content: center; padding: 24px;
+}
+.modal-overlay[hidden] { display: none; }
+.modal {
+  background: var(--bg-2); border: 1px solid var(--border);
+  border-radius: var(--radius); padding: 22px; max-width: 420px; width: 100%;
+  box-shadow: 0 12px 40px rgba(0,0,0,.5);
+}
+.modal p { margin: 0 0 20px; font-size: 15px; line-height: 1.45; word-break: break-word; }
+.modal-actions { display: flex; justify-content: flex-end; gap: 10px; }
+.btn.danger-solid { background: var(--red); border-color: var(--red); color: #fff; font-weight: 600; }
+.btn.danger-solid:hover { background: #e0414f; }
+
 /* ---- lightbox ---- */
 .lightbox {
   position: fixed; inset: 0; z-index: 100;