feat(calls): EC iframe load watchdog + recovery UI; avatar decorations on call tiles

- CallEmbed: 25s load watchdog that fails fast on iframe error / preparing-error /
  timeout instead of hanging on a permanent spinner; additive onLoadError API,
  cleared on ready/capabilities/joined.
- CallView: user-visible "call failed to load" overlay with Retry/Leave (folds +
  tokens) via a new useCallLoadError hook.
- CallMemberCard: wrap the participant avatar in AvatarDecoration so decorations
  render in the call roster (the tile rendered UserAvatar bare while member lists
  already wrapped it).

Addresses LOTUS_BUGS item 3 (avatar decorations in calls) and EC iframe failure monitoring.

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

src/app/features/call/CallMemberCard.tsx

@@ -9,6 +9,7 @@ import { getMemberAvatarMxc, getMemberDisplayName } from '../../utils/room';
 import { useRoom } from '../../hooks/useRoom';
 import { getMxIdLocalPart, mxcUrlToHttp } from '../../utils/matrix';
 import { UserAvatar } from '../../components/user-avatar';
+import { AvatarDecoration } from '../../components/avatar-decoration/AvatarDecoration';
 import { getMouseEventCords } from '../../utils/dom';
 import * as css from './styles.css';
 
@@ -51,14 +52,16 @@ export function CallMemberCard({ member }: CallMemberCardProps) {
       }
     >
       <Box grow="Yes" gap="300" alignItems="Center">
-        <Avatar size="200" radii="400">
-          <UserAvatar
-            userId={userId}
-            src={avatarUrl}
-            alt={name}
-            renderFallback={() => <Icon size="50" src={Icons.User} filled />}
-          />
-        </Avatar>
+        <AvatarDecoration userId={userId}>
+          <Avatar size="200" radii="400">
+            <UserAvatar
+              userId={userId}
+              src={avatarUrl}
+              alt={name}
+              renderFallback={() => <Icon size="50" src={Icons.User} filled />}
+            />
+          </Avatar>
+        </AvatarDecoration>
         <Box grow="Yes">
           <Text size="L400" truncate>
             {name}