Migrate Vite SPA to Hugo (hugo-coder, dark) with WebGPU background

- Hugo static site at root: config, content (home/about/resume/blog + 5 projects),
  data/resume.yaml, custom layouts (gpu background, resume renderer, projects list),
  dark theme with canvas behind content
- gpu-bg/: extracted WebGPU/WebGL2 spiral engine as a Vite sub-package; slim bootstrap
  drops router/overlay/text renderer; fixed uniforms (scene0/dim0); self-contained engine.js
- archive/: retired Vite SPA preserved (router, overlay, data, engine/text orphaned)
- 3-stage Dockerfile (node -> hugo extended/dart-sass -> nginx), static nginx config
- DEPLOYMENT.md handover + README rewrite; pre-hugo rollback tag

.gitmodules

@@ -0,0 +1,3 @@
+[submodule "themes/hugo-coder"]
+	path = themes/hugo-coder
+	url = https://github.com/luizdepra/hugo-coder