feat(calls): rejoin the voice room after a crash, update or reload (#118)

While joined, a device-local record {roomId, deviceId, joinedAt,
lastSeen, mic, video} is written and refreshed every 30 s; a deliberate
hangup (HangupCall/Close) and logout clear it. On the next start, once
the first sync is in and the room's MatrixRTC session has reported its
members (waited for up to 10 s — it fills a moment after sync), a fresh
record (< 10 min) for this device with someone still in the call yields
either a sticky "Rejoin voice?" toast (tap to rejoin) or an automatic
rejoin, per the new Settings → Calls → After a Restart (Ask / Rejoin
automatically / Do nothing; default Ask). Skipped when our own membership
is already live from another device, or only our stale one is left.
Mic/camera state comes from the record (camera still gated by
cameraOnJoin); PTT is applied by startCall as usual.

Pure decision in utils/callRejoin.ts with tests. Verified headless:
reload mid-call → toast → tap → back in the call; hangup → reload → no
toast; auto mode → back in without a prompt.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PPmy3tPq869XDW4njjVaKA

src/app/features/settings/general/General.tsx

@@ -1651,6 +1651,7 @@ function Calls() {
   );
 
   const [pttMode, setPttMode] = useSetting(settingsAtom, 'pttMode');
+  const [callRejoin, setCallRejoin] = useSetting(settingsAtom, 'callRejoinAfterRestart');
   const [pttKey, setPttKey] = useSetting(settingsAtom, 'pttKey');
   const [deafenKey, setDeafenKey] = useSetting(settingsAtom, 'deafenKey');
   const [deafenHotkey, setDeafenHotkey] = useSetting(settingsAtom, 'deafenHotkey');
@@ -1946,6 +1947,21 @@ function Calls() {
         direction="Column"
         gap="400"
       >
+        <SettingTile
+          title="After a Restart"
+          description="If Lotus crashes, reloads or restarts for an update while you are in a voice room, put you back in."
+          after={
+            <SettingsSelect<'ask' | 'auto' | 'off'>
+              value={callRejoin}
+              onChange={setCallRejoin}
+              options={[
+                { value: 'ask', label: 'Ask' },
+                { value: 'auto', label: 'Rejoin automatically' },
+                { value: 'off', label: 'Do nothing' },
+              ]}
+            />
+          }
+        />
         <SettingTile
           title="Push to Talk"
           description="Mute your microphone by default. Hold the PTT key to speak."