fix(desktop): notification click no longer reloads to a dead page (0.1.9/batch62)

Root cause of the persistent "notification opens a dead page / no Join" bug:
openFromNotif gated the in-place open on `window.ME`, but ME is declared with
`let` — which never creates a global property — so window.ME was ALWAYS
undefined and every click hit the full-page-reload fallback. Use bare `ME`.

Also:
- Notifications fire instantly: never block on the DP download. Use the photo
  only if already cached; warm the cache in the background + pre-warm all
  contact DPs on chat load (precache-avatars IPC). Removes the ~2.5s lag.
- Wire call Join/Decline handlers BEFORE firing the OS notification so Join is
  live the instant the invite popup appears (was dead until the toast settled).

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

desktop/main.js

@@ -83,6 +83,13 @@ function avatarToTempPng(src) {
   });
 }
 
+// Pre-warm the DP cache for the renderer's contacts (called after chats load), so the FIRST
+// notification from anyone already has their photo — no per-toast download wait.
+ipcMain.handle('precache-avatars', async (_e, urls = []) => {
+  try { for (const u of (Array.isArray(urls) ? urls : []).slice(0, 100)) { try { await avatarToTempPng(u); } catch (_) {} } } catch (_) {}
+  return true;
+});
+
 // Keep STRONG references to live notifications. Electron/Windows garbage-collects a Notification
 // with no reference, which closed the toast within ~1s and made clicks do nothing.
 const activeNotifs = new Set();
@@ -90,14 +97,16 @@ const activeNotifs = new Set();
 // Resolves {open} when the toast is clicked (renderer then opens that chat), else null.
 ipcMain.handle('reply-notification', async (_e, payload = {}) => {
   if (!Notification.isSupported()) return null;
-  // Do NOT block the toast on the avatar download (that made desktop notifications lag ~15s vs the
-  // browser's instant one). Race it against a cap: use the DP only if it's ready in time. Chat toasts
-  // stay snappy (700ms). CALL toasts (persistent) ring for ~40s, so we can afford to wait longer
-  // (2.5s) to actually show the caller's photo — the whole point of a call notification.
-  const img = await Promise.race([
-    avatarToTempPng(payload.avatar),
-    new Promise((r) => setTimeout(() => r(null), payload.persistent ? 2500 : 700)),
-  ]);
+  // Fire the toast IMMEDIATELY — NEVER block on a download (waiting made notifications lag; a late
+  // call/chat alert is worse than one without a photo). Use the DP only if it's ALREADY cached
+  // (instant). If not, kick off a background fetch so the SAME sender's NEXT notification has it.
+  // Contacts are also pre-warmed on load (precache-avatars), so the photo is usually already cached.
+  let img = null;
+  try {
+    const c = payload.avatar && avatarCache.get(payload.avatar);
+    if (c && fs.existsSync(c)) img = c;
+    else if (payload.avatar) avatarToTempPng(payload.avatar).catch(() => {}); // warm for next time
+  } catch (_) {}
   return await new Promise((resolve) => {
     let done = false;
     let n;