feat(play): hide NPC tokens from the player screen

A token can be hidden per session from the control menu. The GM still sees it, and its path keeps moving. Scene editor grid labels no longer call a removed helper.

Co-authored-by: Cursor <cursoragent@cursor.com>

app/main/players/sceneNpcTokensSessionStore.test.ts

@@ -82,6 +82,22 @@ void test('SceneNpcTokensSessionStore setInactive is session flag', () => {
   assert.equal(s3.byPlacementId.a?.inactive, undefined);
 });
 
+void test('SceneNpcTokensSessionStore hide from players keeps the token for the GM', () => {
+  const store = new SceneNpcTokensSessionStore();
+  const s1 = store.dispatch({ kind: 'setHiddenFromPlayers', placementId: 'a', hidden: true });
+  assert.equal(s1.byPlacementId.a?.hiddenFromPlayers, true);
+  const s2 = store.dispatch({ kind: 'move', placementId: 'a', nx: 0.2, ny: 0.4 });
+  assert.equal(s2.byPlacementId.a?.hiddenFromPlayers, true);
+  assert.equal(s2.byPlacementId.a?.nx, 0.2);
+  const s3 = store.dispatch({ kind: 'setHiddenFromPlayers', placementId: 'a', hidden: false });
+  assert.equal(s3.byPlacementId.a?.hiddenFromPlayers, undefined);
+  assert.equal(s3.byPlacementId.a?.nx, 0.2);
+  const only = store.dispatch({ kind: 'setHiddenFromPlayers', placementId: 'b', hidden: true });
+  store.dispatch({ kind: 'setHiddenFromPlayers', placementId: 'b', hidden: false });
+  assert.equal(store.getState().byPlacementId.b, undefined);
+  assert.ok(only.byPlacementId.b?.hiddenFromPlayers);
+});
+
 void test('SceneNpcTokensSessionStore setSize is session-only and survives move', () => {
   const store = new SceneNpcTokensSessionStore();
   const s1 = store.dispatch({ kind: 'setSize', placementId: 'a', sizeN: 0.2 });