fix(orbit): outbox lost-update recovery and session hardening (#1159)

* fix(orbit): harden the guest outbox — recover lost suggestions, avoid a duplicate outbox

Two outbox robustness issues on the poll-based, non-atomic playlist
transport:

- Lost-update: a track a guest appends to its outbox can be wiped by a
  concurrent host sweep-clear before the host recorded it, leaving the
  suggestion lost AND stuck on "waiting on host" forever (it only clears
  once it reaches the host's play queue). The playlist read-modify-write
  can't be made atomic, so recover: re-send a pending suggestion the host
  hasn't recorded (absent from state.queue) past a grace window — the host
  dedupes by (user, trackId), so it's idempotent — and give up + toast past
  a 45s window so the row stops hanging. New pendingResend planner module
  with unit tests; suggest + tick share ensureTrackInOutbox.

- Duplicate outbox: a transient getPlaylists failure at join was swallowed
  to [], so the existing-outbox check missed and a second outbox was
  created. Distinguish "lookup failed" from "genuinely absent" and retry
  once before falling back to create.

New i18n key for the give-up toast across all locales.

* fix(orbit): reject non-http(s) schemes in share invites

normalizeShareServerUrl only prepends http:// when the server string doesn't
already start with "http", so an invite carrying a scheme like httpx:// or
https-phish:// slips through unchanged. Reject anything whose parsed protocol
isn't http(s) at parse time, before the known-server match. Add round-trip
tests covering the accepted and rejected schemes.

* fix(orbit): read exit-modal role fresh to avoid a stale keydown closure

The exit modal's Enter/Escape handler binds once per open (deps [isOpen]) and
closed over the role prop, so a role change while the modal was up would act
on a stale value. Read role from the store inside the action instead, and drop
the now-unused reactive subscription.

* docs(changelog): consolidate Orbit fixes into one block, add 1159

src/components/OrbitExitModal.tsx

@@ -19,7 +19,6 @@ export default function OrbitExitModal() {
   const { t } = useTranslation();
   const phase        = useOrbitStore(s => s.phase);
   const errorMessage = useOrbitStore(s => s.errorMessage);
-  const role         = useOrbitStore(s => s.role);
   const sessionName  = useOrbitStore(s => s.state?.name);
   const hostName     = useOrbitStore(s => s.state?.host);
 
@@ -31,7 +30,10 @@ export default function OrbitExitModal() {
 
   const onOk = async () => {
     try {
-      if (role === 'guest') await leaveOrbitSession();
+      // Read role fresh from the store — the keydown effect binds once per
+      // open (deps [isOpen]) and would otherwise act on a stale role if it
+      // changed while the modal was up.
+      if (useOrbitStore.getState().role === 'guest') await leaveOrbitSession();
       else useOrbitStore.getState().reset();
     } catch {
       useOrbitStore.getState().reset();