Build the homepage: project cards grouped in 4 sections

Replaces the placeholder index.html with a full personal-projects page
listing all 17 projects across four sections (CipherDolls, decentralized
apps, AI on GPU, Ethereum infrastructure) as cards with name, description,
tech tags, and GitHub links. Adds styles.css (dark-first, light override,
mobile-first responsive grid) and a .dockerignore to keep the build context
clean. Updates the Dockerfile to copy styles.css alongside index.html.

.dockerignore

@@ -0,0 +1,8 @@
+.git
+.gitea
+.agents-workflow
+Dockerfile
+.dockerignore
+AGENTS.md
+README.md
+*.md