refactor(player): E.7 — extract two small file-private helpers (#570)

`emitNormalizationDebug` (debug-mode trace forwarder, 15+ internal call
sites) and `isInOrbitSession` (Orbit-active guard used by next() and the
async fallback paths to suppress local queue extensions, 5 call sites)
move into dedicated modules under src/store/. Both were file-private —
no caller-side changes outside playerStore's own imports.

playerStore 3434 → 3415 LOC.

src/store/orbitSession.ts

@@ -0,0 +1,17 @@
+import { useOrbitStore } from './orbitStore';
+
+/**
+ * True when the user is part of an Orbit session (any role, any phase short
+ * of `idle` / `error` / `ended`). Used by `next()` and its async fallback
+ * callbacks to suppress local queue-extension paths (radio top-up, infinite
+ * queue, queue-exhausted refill) — those would either pop the
+ * `orbitBulkGuard` modal or silently inject tracks the host didn't pick.
+ * Also called inside in-flight `.then()` callbacks so a fetch scheduled
+ * just before the user joined Orbit doesn't fire a `playTrack` after the
+ * join.
+ */
+export function isInOrbitSession(): boolean {
+  const o = useOrbitStore.getState();
+  if (o.role !== 'host' && o.role !== 'guest') return false;
+  return o.phase === 'active' || o.phase === 'joining' || o.phase === 'starting';
+}