feat: Stage 2E physics p95, runtime videos, domain audit, device-test QR

Measure Rapier world.step p95 (~0.2 ms) on GTX 1080, record real route WebMs,
expand runtime/headless hash parity, and document permanent-domain/phone blockers.

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

src/domain/continuousPlayback.test.ts

@@ -22,8 +22,8 @@ import { resolveItem } from '../data/resolveItem';
 
 describe('demoPlaylist', () => {
   it('has classification + safety cases', () => {
-    expect(PLAYLIST_LENGTH).toBe(11);
-    expect(DEMO_PLAYLIST.length).toBe(11);
+    expect(PLAYLIST_LENGTH).toBe(12);
+    expect(DEMO_PLAYLIST.length).toBe(12);
   });
 
   it('has no duplicate case ids', () => {