feat: portfolio redesign with i18n, RBC project showcase, CI/CD

- Add i18n support (EN/ZH) with language toggle
- Redesign header with education dropdown, contact copy buttons
- Add RBC project showcase with bullet points, skills highlighting
- Create terraform-drift placeholder page
- Add ProjectShowcase component with media toggle (image/video)
- Update experience timeline with action-driven descriptions
- Add Docker + Forgejo CI workflow for image builds
- Update K8s manifests for riotpiao.com ingress
- Add DESIGN.md documenting design system patterns

.dockerignore

@@ -0,0 +1,15 @@
+node_modules
+npm-debug.log
+.git
+.gitignore
+README.md
+.env
+.env.local
+.env.*.local
+.next
+.DS_Store
+*.log
+infra
+.claude
+.vscode
+.idea