feat(players): app Players library and circular NPC tokens on scenes

Add userData players/teams, scene npcTokens with hex-inscribed sizing, session scale synced to presentation, and Playwright e2e coverage.

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

app/shared/players/playerTeams.test.ts

@@ -0,0 +1,62 @@
+import assert from 'node:assert/strict';
+import test from 'node:test';
+
+import {
+  assignPlayerToTeam,
+  createPlayerTeamDraft,
+  deletePlayerTeam,
+  normalizeAppPlayerTeams,
+  uniquePlayerTeamName,
+} from './playerTeams';
+import type { AppPlayer, AppPlayerTeam } from '../types/appPlayers';
+import { asPlayerId, asPlayerTeamId } from '../types/ids';
+
+void test('uniquePlayerTeamName appends suffix on collision', () => {
+  const teams: AppPlayerTeam[] = [
+    { id: asPlayerTeamId('t1'), name: 'Alpha', color: '#ffffff' },
+  ];
+  assert.equal(uniquePlayerTeamName('Alpha', teams), 'Alpha (2)');
+  assert.equal(uniquePlayerTeamName('Beta', teams), 'Beta');
+});
+
+void test('normalizeAppPlayerTeams drops invalid and duplicates', () => {
+  const teams = normalizeAppPlayerTeams([
+    { id: 't1', name: 'A', color: '#abc' },
+    { id: 't1', name: 'Dup', color: '#ffffff' },
+    { id: '', name: 'Bad', color: '#ffffff' },
+    null,
+    { id: 't2', name: 'B', color: '#112233' },
+  ]);
+  assert.equal(teams.length, 2);
+  assert.equal(teams[0]!.id, 't1');
+  assert.equal(teams[0]!.color, '#aabbcc'); // #abc → expanded
+  assert.equal(teams[1]!.color, '#112233');
+});
+
+void test('createPlayerTeamDraft has no parentId field', () => {
+  const team = createPlayerTeamDraft('Team', '#ff0000', []);
+  assert.equal(team.name, 'Team');
+  assert.ok(!('parentId' in team));
+});
+
+void test('assignPlayerToTeam and deletePlayerTeam ungroup players', () => {
+  const t1 = asPlayerTeamId('t1');
+  const players: AppPlayer[] = [
+    {
+      id: asPlayerId('p1'),
+      name: 'P',
+      imageRelPath: 'files/a.png',
+      sha256: 'x',
+      teamId: t1,
+      ringColor: '#c9a227',
+      imageOffset: { x: 0, y: 0 },
+      imageScale: 1,
+    },
+  ];
+  const teams: AppPlayerTeam[] = [{ id: t1, name: 'T', color: '#ffffff' }];
+  const assigned = assignPlayerToTeam(players, 'p1', null, new Set([t1]));
+  assert.equal(assigned[0]!.teamId, null);
+  const del = deletePlayerTeam(teams, players, t1);
+  assert.equal(del.teams.length, 0);
+  assert.equal(del.players[0]!.teamId, null);
+});