* refactor(orbit): unify host/guest outbox heartbeat into a shared hook (Phase I)
The outbox-heartbeat effect was duplicated near-verbatim in useOrbitHost
and useOrbitGuest — same 10 s interval, same writeOrbitHeartbeat call,
same cleanup; the only difference is whose name owns the outbox
(OrbitState.host vs the active-server username).
Extract it into useOrbitOutboxHeartbeat(active, outboxPlaylistId,
sessionId, ownName). Host and guest each pass their own name source.
The push/pull state-tick logic stays untouched — that asymmetry is the
real host/guest difference, not duplication.
Behaviour-preserving: the owner name is now a reactive hook arg instead
of a getState() read inside the effect, so the heartbeat starts as soon
as the name is available rather than waiting for an unrelated dep to
change — a strict improvement, unreachable in practice since host name
and username are fixed per session.
* docs(shortcuts): document the shortcut-actions contract (Phase I)
Add a contract reference block to the shortcutActions barrel — the three
independent trigger surfaces (inApp / global / runInMiniWindow), the
surface-independent cli + run fields, the dispatch entry points — and
per-field doc comments on ShortcutActionMeta / ShortcutSlot /
ActionContext / CliContext in shortcutTypes.ts.
Pure documentation, no code change.
Frank Stellmacher