docs: correct the live url and stop restating pinned action versions

The published site is served from the tiennm99dev org, so the documented
tiennm99.github.io url returned 404. The deploy mechanism was also
described as upload-pages-artifact@v3 and deploy-pages@v4 while the
workflow pins v5 of both; the docs now point at the workflow file rather
than restating versions that drift.

README.md

@@ -31,9 +31,9 @@ npm run preview   # Serve build/
 
 ## Deploy
 
-Auto-deploy lên GitHub Pages từ `main` qua `actions/deploy-pages@v4`. Xem `RUNBOOK.md` để rollback / chuyển domain.
+Auto-deploy lên GitHub Pages từ `main`. Cấu hình và phiên bản action nằm trong `.github/workflows/deploy.yml`; xem `RUNBOOK.md` để rollback / chuyển domain.
 
-Live URL: https://tiennm99.github.io/mathmax/
+Live URL: https://tiennm99dev.github.io/mathmax/
 
 ## Architecture
 

RUNBOOK.md

@@ -4,9 +4,9 @@
 
 Production deploys from `main` via GitHub Actions (`.github/workflows/deploy.yml`).
 
-- Live URL: `https://tiennm99.github.io/mathmax/`
+- Live URL: `https://tiennm99dev.github.io/mathmax/`
 - Build: `npm run build` (SvelteKit static, output to `build/`)
-- Deploy mechanism: `actions/upload-pages-artifact@v3` + `actions/deploy-pages@v4`
+- Deploy mechanism: `actions/upload-pages-artifact` + `actions/deploy-pages`, phiên bản pin trong `.github/workflows/deploy.yml`
 - Concurrency: `pages-deploy` group, cancel-in-progress disabled (so a force-pushed retry doesn't abort an in-flight rollback)
 
 ## Rollback
@@ -33,7 +33,7 @@ Per plan, buy a `.vn` / `.com.vn` domain only when ANY of:
 2. **1 organic teacher share** (Facebook group, Zalo, or school chat — verified, not founder-initiated), OR
 3. **≥5 modules shipped** (signals content sustainability and amortizes the domain cost)
 
-If none hit within 90 days of soft launch, stay on `tiennm99.github.io/mathmax/`.
+If none hit within 90 days of soft launch, stay on `tiennm99dev.github.io/mathmax/`.
 
 When the trigger fires: