fix: add nginx SPA fallback for BrowserRouter routing

Root cause: Docker container was 4 days old and nginx had no
try_files fallback for SPA routes like /details.

Changes:
- Add nginx.conf with try_files $uri $uri/ /index.html
- Update Dockerfile to copy nginx config
- Add production browser QA script

Production verified:
- https://arhipovdan.ru/ shows full-screen 3D demo
- https://arhipovdan.ru/details shows detailed page

docs/PRODUCTION_SYNC_REPORT.md

@@ -0,0 +1,181 @@
+# Production Sync Report
+
+**Date:** 2026-07-09  
+**Status:** Resolved
+
+---
+
+## Root Cause
+
+### Почему production не менялся:
+
+1. **Docker контейнер не пересобран**
+   - Контейнер `owl-web-1` был создан **4 дня назад** и не обновлялся
+   - Все коммиты с MainPage, DetailsPage, routing были сделаны, но docker не пересобирался
+
+2. **Nginx не настроен для SPA routing**
+   - `/details` возвращал 404 потому что nginx искал физический файл
+   - Для BrowserRouter нужен fallback на `index.html`
+
+---
+
+## What Was Fixed
+
+### 1. Docker rebuild
+
+```bash
+docker compose -p owl -f docker-compose.server.yml up -d --build
+```
+
+### 2. Nginx SPA configuration
+
+Создан файл `nginx.conf`:
+
+```nginx
+server {
+    listen 80;
+    server_name localhost;
+    root /usr/share/nginx/html;
+    index index.html;
+
+    location / {
+        try_files $uri $uri/ /index.html;
+    }
+
+    location /assets/ {
+        expires 1y;
+        add_header Cache-Control "public, immutable";
+    }
+}
+```
+
+### 3. Dockerfile update
+
+```dockerfile
+FROM nginx:alpine AS runtime
+COPY --from=build /app/dist /usr/share/nginx/html
+COPY nginx.conf /etc/nginx/conf.d/default.conf  # Added
+EXPOSE 80
+CMD ["nginx", "-g", "daemon off;"]
+```
+
+---
+
+## Files Changed
+
+| File | Change |
+|------|--------|
+| `nginx.conf` | Created (SPA fallback) |
+| `Dockerfile` | Added nginx.conf copy |
+| `scripts/test_production.py` | Created (browser QA) |
+
+---
+
+## Production Verification
+
+### curl results
+
+```
+https://arhipovdan.ru/        → 200 OK
+https://arhipovdan.ru/details → 200 OK
+```
+
+### Browser QA (production)
+
+| Check | Result |
+|-------|--------|
+| Play button | ✓ |
+| Details link | ✓ |
+| HUD present | ✓ |
+| Progress dots | 8 ✓ |
+| HeroSection absent on / | ✓ |
+| ProductDemo absent on / | ✓ |
+| Header on /details | ✓ |
+| HeroSection on /details | ✓ |
+| No console errors | ✓ |
+
+---
+
+## Screenshots
+
+```
+docs/production_sync_screenshots/
+├── prod_home_after_deploy.png
+└── prod_details_after_deploy.png
+```
+
+### Main page (/)
+
+![Home](production_sync_screenshots/prod_home_after_deploy.png)
+
+- Full-screen 3D demo
+- HUD: Item, Status, Category, Command, Speed, Case 1/8
+- Play Demo button
+- Details → link
+- 8 progress dots
+
+### Details page (/details)
+
+![Details](production_sync_screenshots/prod_details_after_deploy.png)
+
+- Back to Full-Screen Demo link
+- Header with navigation
+- HeroSection
+- Detection/Classification/Command/Routing stepper
+- Buttons: Запустить демо, Показать сценарии, Инженерный режим
+
+---
+
+## Build/Test Results
+
+```
+✓ npm run build — success
+✓ npm run test — 59 tests passed
+✓ docker rebuild — success
+✓ curl / — 200
+✓ curl /details — 200
+✓ Browser QA — all checks passed
+```
+
+---
+
+## Remaining Risks
+
+1. **Browser cache** — Users may need to hard-refresh (Ctrl+Shift+R)
+2. **CDN cache** — If using CDN, may need purge
+
+---
+
+## Commands for Commit/Push
+
+```bash
+cd /opt/arhipovdan/app
+
+git add \
+  nginx.conf \
+  Dockerfile \
+  scripts/test_production.py \
+  docs/PRODUCTION_SYNC_REPORT.md \
+  docs/production_sync_screenshots/
+
+git commit -m "$(cat <<'EOF'
+fix: add nginx SPA fallback for BrowserRouter routing
+
+Root cause: Docker container was 4 days old and nginx had no
+try_files fallback for SPA routes like /details.
+
+Changes:
+- Add nginx.conf with try_files $uri $uri/ /index.html
+- Update Dockerfile to copy nginx config
+- Add production browser QA script
+
+Production verified:
+- https://arhipovdan.ru/ shows full-screen 3D demo
+- https://arhipovdan.ru/details shows detailed page
+EOF
+)"
+
+git push origin dan_branch
+```
+
+**DO NOT RUN** — commit/push not requested.