feat: SPA routing, projects/resume sections, deployment infra

- Add client-side router with History API pushState (router.ts, pages.ts)
- Extend overlay with projects grid/category/detail views and resume section
- Add Gitea CI/CD workflow and webhook deployment server
- Improve Docker Compose with nginx reverse proxy config
- Add deployment script and .env.example

.gitignore

@@ -17,3 +17,6 @@ test-*.js
 
 # LaTeX resume (unrelated to the site)
 resume.tex
+
+# CI/CD — webhook secret + deployment env
+.env