feat(web): complete groups/contacts/favorites/settings/calls/system domains + extensive review-round fixes

Rounds out the full rewrite with the remaining feature domains: group
management (admin panel, mute, files, announcements, QR-based invite/join),
contacts (friend profile, add-friend, blocklist, new-friends), favorites
(real media rendering across text/image/video/voice/file/link), settings
(profile/security/privacy/general/about), calls (Agora-backed audio/video
signaling + call history), and system messages/file assistant.

Also folds in a large batch of live-verified fixes surfaced by repeated
fresh code-review passes and hands-on E2E testing against the real
backend, including: WS reconnect not resubscribing any topic after a
disconnect, missing x-im-client-mid on every send path (protocol
compliance for retry dedup), group mute/member-settings/self-profile
endpoint corrections, relationship-state type fixes across search/QR/
friend-profile, tenant-switch logout gap, password-policy now read from
the real per-tenant config instead of guessed, NavRail highlight/
aria-current desync, several call-state-machine races, and responsive
layout fixes across all four breakpoints (mobile/tablet/laptop/desktop)
including a full mobile rebuild of favorites, call UI, and the settings
home/sub-list split.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

web/src/app/Toast.tsx

@@ -29,7 +29,12 @@ export function Toast({ message, variant = 'success', onDone }: ToastProps) {
   return (
     <div
       role="status"
-      className="fixed bottom-8 left-1/2 z-50 flex -translate-x-1/2 items-center gap-2 rounded-lg bg-text-heading/94 px-4 py-3 text-sm text-white"
+      // `position:fixed` resolves against the viewport, not AppShell's own Outlet box -- below 640px
+      // that viewport bottom is where the persistent BottomTabBar (82px tall) already sits, so the
+      // unconditional `bottom-12` this used to be sat squarely on top of it on every phone-width
+      // screen, for every Toast call site in the app. `sm:bottom-12` restores the original 48px gap
+      // once the tab bar is gone (>=640px, NavRail shown instead).
+      className="fixed bottom-[130px] left-1/2 z-50 flex -translate-x-1/2 items-center gap-2 rounded-lg bg-text-heading/94 px-4 py-2.5 text-sm text-white sm:bottom-12"
     >
       <Icon name={variant === 'error' ? 'error' : 'check_circle'} className={`text-[18px] ${variant === 'error' ? 'text-danger-text' : 'text-online'}`} />
       {message}