feat(orbit): prompt to rejoin a session after an app restart

On launch, if a breadcrumb points at a still-alive session on the active
server, a modal offers a one-click rejoin with a 30s auto-rejoin countdown
(host resumes hosting, guest rejoins via the normal path). Declining, Escape,
or a failed attempt wipes the breadcrumb. Copy added across all nine locales.

src/app/AppShell.tsx

@@ -23,6 +23,7 @@ import GlobalConfirmModal from '../components/GlobalConfirmModal';
 import ThemeMigrationNotice from '../components/ThemeMigrationNotice';
 import OrbitAccountPicker from '../components/OrbitAccountPicker';
 import OrbitHelpModal from '../components/OrbitHelpModal';
+import OrbitReconnectModal from '../components/OrbitReconnectModal';
 import TooltipPortal from '../components/TooltipPortal';
 import OverlayScrollArea from '../components/OverlayScrollArea';
 import {
@@ -322,6 +323,7 @@ export function AppShell() {
       <ThemeMigrationNotice />
       <OrbitAccountPicker />
       <OrbitHelpModal />
+      <OrbitReconnectModal />
       {!perfFlags.disableTooltipPortal && <TooltipPortal />}
       <AppUpdater />
     </div>

src/components/OrbitReconnectModal.tsx

@@ -0,0 +1,152 @@
+import { useCallback, useEffect, useRef, useState } from 'react';
+import { createPortal } from 'react-dom';
+import { useTranslation } from 'react-i18next';
+import { useOrbitStore } from '../store/orbitStore';
+import { useAuthStore } from '../store/authStore';
+import { showToast } from '../utils/ui/toast';
+import {
+  clearOrbitLastSession,
+  findSessionPlaylistId,
+  joinOrbitSession,
+  ORBIT_RECONNECT_COUNTDOWN_S,
+  ORBIT_RECONNECT_MAX_AGE_MS,
+  readOrbitLastSession,
+  readOrbitState,
+  resumeOrbitSessionAsHost,
+  type OrbitLastSession,
+} from '../utils/orbit';
+
+/**
+ * Orbit — reconnect prompt shown at startup when the app was restarted while a
+ * session was active. The in-memory Orbit store is gone after a restart, but
+ * the `lastSession` breadcrumb survives; this verifies the session is still
+ * alive on the server and offers a one-click rejoin with a countdown that
+ * auto-rejoins when it reaches zero.
+ *
+ * Host breadcrumbs resume hosting (`resumeOrbitSessionAsHost`); guest
+ * breadcrumbs rejoin via the normal `joinOrbitSession` path. Declining /
+ * Escape / a failed attempt wipes the breadcrumb so it isn't offered again.
+ */
+export default function OrbitReconnectModal() {
+  const { t } = useTranslation();
+  const isLoggedIn = useAuthStore(s => s.isLoggedIn);
+  const activeServerId = useAuthStore(s => s.activeServerId);
+  const orbitRole = useOrbitStore(s => s.role);
+
+  const [candidate, setCandidate] = useState<OrbitLastSession | null>(null);
+  const [secondsLeft, setSecondsLeft] = useState(ORBIT_RECONNECT_COUNTDOWN_S);
+  const [busy, setBusy] = useState(false);
+  const ranRef = useRef(false);
+  const firedRef = useRef(false);
+
+  // One-shot startup preflight: is there a live session worth offering?
+  useEffect(() => {
+    if (ranRef.current) return;
+    if (!isLoggedIn || !activeServerId) return; // wait for auth hydration
+    if (orbitRole !== null) return;             // already bound to a session
+    ranRef.current = true;
+
+    const rec = readOrbitLastSession();
+    if (!rec || rec.serverId !== activeServerId) return; // none / different server
+
+    let cancelled = false;
+    void (async () => {
+      try {
+        const sessionPlaylistId = await findSessionPlaylistId(rec.sid);
+        if (!sessionPlaylistId) { clearOrbitLastSession(); return; }
+        const state = await readOrbitState(sessionPlaylistId);
+        if (!state || state.ended) { clearOrbitLastSession(); return; }
+        // Too long since the last host snapshot → treat as dead, don't offer.
+        if (Date.now() - (state.positionAt ?? 0) > ORBIT_RECONNECT_MAX_AGE_MS) {
+          clearOrbitLastSession();
+          return;
+        }
+        // A host breadcrumb only resumes if we're still the session's host.
+        if (rec.role === 'host' && state.host !== useAuthStore.getState().getActiveServer()?.username) {
+          clearOrbitLastSession();
+          return;
+        }
+        if (!cancelled) setCandidate(rec);
+      } catch {
+        /* network hiccup — keep the breadcrumb, just skip the prompt this launch */
+      }
+    })();
+    return () => { cancelled = true; };
+  }, [isLoggedIn, activeServerId, orbitRole]);
+
+  const doReconnect = useCallback(async () => {
+    if (firedRef.current) return; // guard countdown + manual click racing
+    const rec = candidate;
+    if (!rec) return;
+    firedRef.current = true;
+    setBusy(true);
+    try {
+      if (rec.role === 'host') await resumeOrbitSessionAsHost(rec.sid);
+      else await joinOrbitSession(rec.sid);
+      setCandidate(null); // success → store now bound, modal hides
+    } catch {
+      clearOrbitLastSession();
+      showToast(t('orbit.reconnect.failed'), 4000, 'error');
+      setCandidate(null);
+    } finally {
+      setBusy(false);
+    }
+  }, [candidate, t]);
+
+  const stayOut = useCallback(() => {
+    clearOrbitLastSession();
+    setCandidate(null);
+  }, []);
+
+  // Countdown → auto-rejoin at zero. Paused while a reconnect is in flight.
+  useEffect(() => {
+    if (!candidate || busy) return;
+    if (secondsLeft <= 0) { void doReconnect(); return; }
+    const id = window.setTimeout(() => setSecondsLeft(s => s - 1), 1000);
+    return () => window.clearTimeout(id);
+  }, [candidate, busy, secondsLeft, doReconnect]);
+
+  // Enter → rejoin now; Escape → stay out (explicit dismissal, no auto-rejoin).
+  useEffect(() => {
+    if (!candidate) return;
+    const onKey = (e: KeyboardEvent) => {
+      if (e.key === 'Enter') { e.preventDefault(); void doReconnect(); }
+      else if (e.key === 'Escape') { e.preventDefault(); stayOut(); }
+    };
+    window.addEventListener('keydown', onKey);
+    return () => window.removeEventListener('keydown', onKey);
+  }, [candidate, doReconnect, stayOut]);
+
+  if (!candidate) return null;
+
+  const body = candidate.role === 'host'
+    ? t('orbit.reconnect.bodyHost', { name: candidate.sessionName })
+    : t('orbit.reconnect.bodyGuest', { host: candidate.hostUsername, name: candidate.sessionName });
+
+  return createPortal(
+    <div
+      className="modal-overlay orbit-exit-overlay"
+      onClick={e => { if (e.target === e.currentTarget) stayOut(); }}
+      role="dialog"
+      aria-modal="true"
+      aria-labelledby="orbit-reconnect-title"
+    >
+      <div className="modal-content orbit-exit-modal">
+        <h3 id="orbit-reconnect-title" className="orbit-exit-modal__title">{t('orbit.reconnect.title')}</h3>
+        <p className="orbit-exit-modal__body">{body}</p>
+        {!busy && (
+          <p className="orbit-reconnect-countdown">{t('orbit.reconnect.autoIn', { seconds: secondsLeft })}</p>
+        )}
+        <div className="orbit-exit-modal__actions">
+          <button type="button" className="btn btn-ghost" onClick={stayOut} disabled={busy}>
+            {t('orbit.reconnect.stayOut')}
+          </button>
+          <button type="button" className="btn btn-primary" onClick={() => void doReconnect()} disabled={busy} autoFocus>
+            {busy ? t('orbit.reconnect.reconnecting') : t('orbit.reconnect.rejoin')}
+          </button>
+        </div>
+      </div>
+    </div>,
+    document.body,
+  );
+}

src/locales/de/orbit.ts

@@ -1,4 +1,14 @@
 export const orbit = {
+  reconnect: {
+    title: 'Wieder in deine Orbit-Session?',
+    bodyHost: 'Du hast „{{name}}" gehostet. Dort weitermachen, wo du aufgehört hast?',
+    bodyGuest: '{{host}} hostet „{{name}}". Wieder beitreten?',
+    autoIn: 'Automatisch in {{seconds}}s',
+    rejoin: 'Wieder rein',
+    stayOut: 'Draußen bleiben',
+    reconnecting: 'Trete bei…',
+    failed: 'Wiedereinstieg fehlgeschlagen — die Session ist vielleicht beendet.',
+  },
   triggerLabel: 'Orbit',
   triggerTooltip: 'Gemeinsame Hör-Session starten oder beitreten',
   launchCreate: 'Session erstellen',

src/locales/en/orbit.ts

@@ -1,4 +1,14 @@
 export const orbit = {
+  reconnect: {
+    title: 'Rejoin your Orbit session?',
+    bodyHost: 'You were hosting "{{name}}". Pick the session back up where you left off?',
+    bodyGuest: '{{host}} is hosting "{{name}}". Rejoin the session?',
+    autoIn: 'Auto-rejoin in {{seconds}}s',
+    rejoin: 'Rejoin',
+    stayOut: 'Stay out',
+    reconnecting: 'Rejoining…',
+    failed: "Couldn't rejoin — the session may have ended.",
+  },
   triggerLabel: 'Orbit',
   triggerTooltip: 'Start or join a shared listening session',
   launchCreate: 'Create a session',

src/locales/es/orbit.ts

@@ -1,4 +1,14 @@
 export const orbit = {
+  reconnect: {
+    title: '¿Volver a tu sesión de Orbit?',
+    bodyHost: 'Estabas alojando «{{name}}». ¿Retomar la sesión donde la dejaste?',
+    bodyGuest: '{{host}} está alojando «{{name}}». ¿Volver a unirte?',
+    autoIn: 'Reconexión automática en {{seconds}} s',
+    rejoin: 'Volver a unirse',
+    stayOut: 'Quedarse fuera',
+    reconnecting: 'Uniéndose…',
+    failed: 'No se pudo volver a unir: puede que la sesión haya terminado.',
+  },
   triggerLabel: 'Orbit',
   triggerTooltip: 'Iniciar o unirse a una sesión de escucha compartida',
   launchCreate: 'Crear una sesión',

src/locales/fr/orbit.ts

@@ -1,4 +1,14 @@
 export const orbit = {
+  reconnect: {
+    title: 'Rejoindre votre session Orbit ?',
+    bodyHost: 'Vous hébergiez « {{name}} ». Reprendre la session là où vous l\'avez laissée ?',
+    bodyGuest: '{{host}} héberge « {{name}} ». Rejoindre la session ?',
+    autoIn: 'Reconnexion auto dans {{seconds}} s',
+    rejoin: 'Rejoindre',
+    stayOut: 'Rester en dehors',
+    reconnecting: 'Connexion…',
+    failed: 'Impossible de rejoindre — la session est peut-être terminée.',
+  },
   triggerLabel: 'Orbit',
   triggerTooltip: 'Démarrer ou rejoindre une session d\'écoute partagée',
   launchCreate: 'Créer une session',

src/locales/nb/orbit.ts

@@ -1,4 +1,14 @@
 export const orbit = {
+  reconnect: {
+    title: 'Bli med i Orbit-økten igjen?',
+    bodyHost: 'Du var vert for «{{name}}». Fortsette økten der du slapp?',
+    bodyGuest: '{{host}} er vert for «{{name}}». Bli med igjen?',
+    autoIn: 'Kobler til automatisk om {{seconds}} s',
+    rejoin: 'Bli med igjen',
+    stayOut: 'Hold deg utenfor',
+    reconnecting: 'Kobler til…',
+    failed: 'Kunne ikke bli med igjen – økten kan være avsluttet.',
+  },
   triggerLabel: 'Orbit',
   triggerTooltip: 'Start eller bli med i en delt lytteøkt',
   launchCreate: 'Opprett en økt',

src/locales/nl/orbit.ts

@@ -1,4 +1,14 @@
 export const orbit = {
+  reconnect: {
+    title: 'Weer in je Orbit-sessie?',
+    bodyHost: 'Je hostte "{{name}}". De sessie hervatten waar je was gebleven?',
+    bodyGuest: '{{host}} host "{{name}}". Weer deelnemen?',
+    autoIn: 'Automatisch over {{seconds}} s',
+    rejoin: 'Opnieuw deelnemen',
+    stayOut: 'Erbuiten blijven',
+    reconnecting: 'Deelnemen…',
+    failed: 'Kon niet opnieuw deelnemen — de sessie is mogelijk beëindigd.',
+  },
   triggerLabel: 'Orbit',
   triggerTooltip: 'Een gedeelde luistersessie starten of eraan deelnemen',
   launchCreate: 'Sessie aanmaken',

src/locales/ro/orbit.ts

@@ -1,4 +1,14 @@
 export const orbit = {
+  reconnect: {
+    title: 'Reintri în sesiunea Orbit?',
+    bodyHost: 'Găzduiai „{{name}}". Reiei sesiunea de unde ai rămas?',
+    bodyGuest: '{{host}} găzduiește „{{name}}". Reintri în sesiune?',
+    autoIn: 'Reconectare automată în {{seconds}} s',
+    rejoin: 'Reintră',
+    stayOut: 'Rămâi afară',
+    reconnecting: 'Se reconectează…',
+    failed: 'Nu s-a putut reintra — sesiunea s-ar putea să se fi încheiat.',
+  },
   triggerLabel: 'Orbit',
   triggerTooltip: 'Pornește sau intră în o sesiune de ascultare distribuită',
   launchCreate: 'Crează o sesiune',

src/locales/ru/orbit.ts

@@ -1,4 +1,14 @@
 export const orbit = {
+  reconnect: {
+    title: 'Вернуться в сессию Orbit?',
+    bodyHost: 'Вы вели «{{name}}». Продолжить с того места, где остановились?',
+    bodyGuest: '{{host}} ведёт «{{name}}». Снова присоединиться?',
+    autoIn: 'Автоматически через {{seconds}} с',
+    rejoin: 'Вернуться',
+    stayOut: 'Остаться',
+    reconnecting: 'Подключение…',
+    failed: 'Не удалось вернуться — возможно, сессия завершена.',
+  },
   triggerLabel: 'Orbit',
   triggerTooltip: 'Начать или присоединиться к совместной сессии прослушивания',
   launchCreate: 'Создать сессию',

src/locales/zh/orbit.ts

@@ -1,4 +1,14 @@
 export const orbit = {
+  reconnect: {
+    title: '重新加入你的 Orbit 会话？',
+    bodyHost: '你之前在主持「{{name}}」。从上次离开的地方继续会话吗？',
+    bodyGuest: '{{host}} 正在主持「{{name}}」。重新加入会话吗？',
+    autoIn: '{{seconds}} 秒后自动重连',
+    rejoin: '重新加入',
+    stayOut: '不加入',
+    reconnecting: '正在加入…',
+    failed: '无法重新加入——会话可能已结束。',
+  },
   triggerLabel: 'Orbit',
   triggerTooltip: '开始或加入共享收听会话',
   launchCreate: '创建会话',

src/styles/components/orbit-session-top-strip.css

@@ -400,6 +400,16 @@
 .orbit-exit-modal__actions {
   display: flex;
   justify-content: center;
+  gap: 10px;
+}
+
+/* Reconnect prompt — auto-rejoin countdown line above the actions. */
+.orbit-reconnect-countdown {
+  margin: 0 0 16px;
+  font-size: 12px;
+  font-variant-numeric: tabular-nums;
+  color: var(--text-muted);
+  text-align: center;
 }
 
 /* ── Topbar "start Orbit" trigger — same form as Live, accent-tinted ── */