fix(calls): the call-failed screen gets a Try again button (#301)

"The call failed to load… try again" only offered Back, so the user had
to back out and press Join again. Try again starts a fresh embed for
the same room with the same mic/camera/sound (which disposes the hung
one); Back stays as the secondary action.

Fixes #301

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017PCb59uY3UKqDqt7B6hzd5

src/app/features/call/CallView.tsx

@@ -6,12 +6,13 @@ import {
   useCallJoined,
   useCallEmbedPlacementSync,
   useCallLoadError,
+  useCallStart,
 } from '../../hooks/useCallEmbed';
 import { callEmbedAtom } from '../../state/callEmbed';
 import { ContainerColor } from '../../styles/ContainerColor.css';
 import { PrescreenControls } from './PrescreenControls';
 import { usePowerLevelsContext } from '../../hooks/usePowerLevels';
-import { useRoom } from '../../hooks/useRoom';
+import { useIsDirectRoom, useRoom } from '../../hooks/useRoom';
 import { useRoomCreators } from '../../hooks/useRoomCreators';
 import { useRoomPermissions } from '../../hooks/useRoomPermissions';
 import { useMatrixClient } from '../../hooks/useMatrixClient';
@@ -160,6 +161,16 @@ function CallLoadErrorMessage() {
   // prescreen, where they can choose to join again.
   const dismiss = () => setCallEmbed(undefined);
 
+  // [Gitea #301] Try again: start a fresh embed for the same room with the
+  // same mic/camera/sound choices (starting one disposes the hung one).
+  const callEmbed = useCallEmbed();
+  const startCall = useCallStart(useIsDirectRoom());
+  const retry = () => {
+    if (!callEmbed) return;
+    const { room, control } = callEmbed;
+    startCall(room, { microphone: control.microphone, video: control.video, sound: control.sound });
+  };
+
   return (
     <Box
       className={css.CallViewContent}
@@ -173,6 +184,9 @@ function CallLoadErrorMessage() {
         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={retry} disabled={!callEmbed}>
+          <Text size="B400">Try again</Text>
+        </Button>
         <Button variant="Secondary" fill="Soft" size="300" radii="400" onClick={dismiss}>
           <Text size="B400">Back</Text>
         </Button>