fix: stabilize public demo and align sorter twins

Document arhipovdan.ru DNS/TLS blocker, add production smoke and GPU
perf tooling, unify twin layout, and expand visual regression coverage.

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

docs/FINAL_DEMO_READINESS.md

@@ -0,0 +1,40 @@
+# FINAL_DEMO_READINESS
+
+Дата: 2026-07-15
+Ветка: `feature/maximum-demo-realism`
+Production release (не тронут этим коммитом): `20260715-1712` / `index-ncgt6PBL.js`
+
+## Status board
+
+| Область | Статус | Комментарий |
+| ------- | ------ | ----------- |
+| Git | PASS | Feature branch clean after commit; no push |
+| Production container | PASS | `owl-web-1` на `:3100`, bundle `index-ncgt6PBL.js` |
+| Permanent domain | BLOCKED_EXTERNAL | `arhipovdan.ru` → openresty 404 / TLS SNI fail |
+| TLS | BLOCKED_EXTERNAL | Нет SNI-сертификата на destination IP |
+| Main route | PASS | Local + Quick Tunnel |
+| Details route | PASS | SPA fallback 200 |
+| Unit tests | PASS | 166 |
+| E2E | PASS | 15 (excl. production) |
+| Visual regression | PASS | 10 snapshots |
+| GPU performance | PARTIAL | SwiftShader/xvfb only; hardware baseline blocked in coder |
+| Safety scenarios | PASS | Jam + E-stop e2e |
+| Rollback | PASS | Tag `backup/pre-maximum-demo-realism-20260715` + docker rename |
+| Agent safety | PASS | Worktree / dry-run / no auto DNS |
+
+## Verdict
+
+```text
+READY WITH EXTERNAL DOMAIN BLOCKER
+```
+
+Live demo **можно** вести с:
+
+- `http://127.0.0.1:3100/` (локально), или
+- актуального Quick Tunnel `https://invitations-based-characters-accent.trycloudflare.com/`
+
+Постоянный домен `https://arhipovdan.ru/` **не готов** до DNS/proxy фикса пользователем (см. `PUBLIC_DOMAIN_DIAGNOSTIC.md`).
+
+## Next deploy note
+
+Новый код (perf overlay, twin layout, visual snapshots) собран как `index-DEbogfOZ.js` в `dist/`, но **не** задеплоен в `owl-web-1`, чтобы не нарушить работающий production. Redeploy — отдельный шаг после доменного фикса или явного запроса.