Offline: newest 100 conversations; notifications no longer wait silently

Offline access keeps the newest 100 Inbox conversations (the list's first two
pages, saved as the app asks for them) plus recently opened ones, up to 130.

Turning notifications on in a browser that holds the permission request
without showing it (Opera, Chrome's quiet prompts) said nothing and never
finished. After a few seconds it now says how to allow notifications for the
site, and carries on by itself as soon as they are allowed.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

frontend/src/i18n/en.ts

@@ -591,7 +591,7 @@ export const en = {
   "offline.cantReach": "Can't reach the server.",
   "offline.settingTitle": "Offline access",
   "offline.settingHelp":
-    "Keep your newest 50 Inbox conversations, and the ones you open, on this device, so you can read them without a connection. They are stored unencrypted in this browser and removed when you sign out — leave this off on shared computers.",
+    "Keep your newest 100 Inbox conversations, and the ones you open, on this device, so you can read them without a connection. They are stored unencrypted in this browser and removed when you sign out — leave this off on shared computers.",
   "offline.settingStatus": "{count} conversations saved · {size} · updated {when}",
   "offline.settingStatusNoTime": "{count} conversations saved · {size}",
   "offline.settingSaving": "Saving recent mail…",
@@ -606,6 +606,8 @@ export const en = {
     "Notifications are blocked for this site in your browser. Allow them in the browser's site settings, then turn this on.",
   "push.unsupported": "Not available here: this browser can't show notifications from a website, or the app isn't opened over HTTPS.",
   "push.notAllowed": "Notifications weren't allowed.",
+  "push.waiting":
+    "Waiting for your browser's permission. If it didn't ask, click the icon at the left of the address bar and set Notifications to Allow — they turn on by themselves then.",
   "push.failed": "Couldn't turn notifications on.",
   "install.entry": "Install app",
   "install.title": "Install Ultimo",