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/CallView.tsx

@@ -1,6 +1,13 @@
 import React, { RefObject, useRef } from 'react';
-import { Badge, Box, color, Header, Scroll, Text, toRem } from 'folds';
-import { useCallEmbed, useCallJoined, useCallEmbedPlacementSync } from '../../hooks/useCallEmbed';
+import { useSetAtom } from 'jotai';
+import { Badge, Box, Button, color, Header, Icon, Icons, Scroll, Text, toRem } from 'folds';
+import {
+  useCallEmbed,
+  useCallJoined,
+  useCallEmbedPlacementSync,
+  useCallLoadError,
+} from '../../hooks/useCallEmbed';
+import { callEmbedAtom } from '../../state/callEmbed';
 import { ContainerColor } from '../../styles/ContainerColor.css';
 import { PrescreenControls } from './PrescreenControls';
 import { usePowerLevelsContext } from '../../hooks/usePowerLevels';
@@ -153,6 +160,37 @@ function CallPrescreen() {
   );
 }
 
+function CallLoadErrorMessage() {
+  const setCallEmbed = useSetAtom(callEmbedAtom);
+
+  // Disposing the embed tears down the hung iframe and returns the user to the
+  // prescreen, from which they can join again ("Retry") or simply walk away.
+  const dismiss = () => setCallEmbed(undefined);
+
+  return (
+    <Box
+      className={css.CallViewContent}
+      direction="Column"
+      alignItems="Center"
+      justifyContent="Center"
+      gap="300"
+    >
+      <Icon src={Icons.Warning} size="400" style={{ color: color.Critical.Main }} />
+      <Text style={{ color: color.Critical.Main }} size="L400" align="Center">
+        The call failed to load. Check your connection and try again.
+      </Text>
+      <Box gap="200" alignItems="Center">
+        <Button variant="Primary" size="300" radii="400" onClick={dismiss}>
+          <Text size="B400">Retry</Text>
+        </Button>
+        <Button variant="Secondary" fill="Soft" size="300" radii="400" onClick={dismiss}>
+          <Text size="B400">Leave</Text>
+        </Button>
+      </Box>
+    </Box>
+  );
+}
+
 type CallJoinedProps = {
   containerRef: RefObject<HTMLDivElement>;
   joined: boolean;
@@ -175,8 +213,13 @@ export function CallView() {
 
   const callEmbed = useCallEmbed();
   const callJoined = useCallJoined(callEmbed);
+  const loadError = useCallLoadError(callEmbed);
 
-  const currentJoined = callEmbed?.roomId === room.roomId && callJoined;
+  const isCurrentRoom = callEmbed?.roomId === room.roomId;
+  const currentJoined = isCurrentRoom && callJoined;
+  // Show the recovery UI when this room's embed failed to load and we never
+  // made it into the call (a hung iframe / blank spinner otherwise).
+  const showLoadError = isCurrentRoom && !currentJoined && Boolean(loadError);
 
   return (
     <Box
@@ -184,8 +227,9 @@ export function CallView() {
       style={{ minWidth: toRem(280) }}
       grow="Yes"
     >
-      {!currentJoined && <CallPrescreen />}
-      <CallJoined joined={currentJoined} containerRef={callContainerRef} />
+      {showLoadError && <CallLoadErrorMessage />}
+      {!currentJoined && !showLoadError && <CallPrescreen />}
+      {!showLoadError && <CallJoined joined={currentJoined} containerRef={callContainerRef} />}
     </Box>
   );
 }