Add read-only terminal virtual filesystem

[cursor]

Issue

Title

Add a read-only portfolio filesystem to the terminal emulator

Problem

The terminal help advertised shell-like commands such as pwd and cd, but the implementation was mostly stubbed: pwd always returned /home/guest, cd rejected every real path, and ls only listed commands. This limited the site's stated goal of terminal emulation.

Proposed improvement

Implement a generated, read-only /home/guest virtual filesystem backed by existing portfolio JSON data. Users should be able to navigate and inspect portfolio content using familiar shell commands.

Acceptance criteria

• pwd prints the current virtual working directory.
• cd [path], cd ~, cd .., and cd - update the current directory and prompt path.
• ls [-la] [path] lists generated files/directories, while ls --commands preserves the command catalog.
• cat [file] reads generated portfolio files.
• Path tab completion works for cd, ls, and cat.
• README/help/man text documents the feature.
• Unit tests cover path resolution, listing, reading, completions, and edge cases.

Summary

• Added a pure virtual filesystem helper layer in src/lib/terminal/index.js generated from projects, repos, skills, experience, posts, and site config.
• Wired the browser runtime to track current/previous directories, update prompts, support pwd, cd, ls, cat, and path completion.
• Replaced the duplicated runtime command list with the shared exported COMMAND_LIST and documented filesystem usage in help/man pages and README.

Testing

• Pre-push pnpm check passed: lint, Prettier format check, Vitest coverage, and Astro production build.
• Vitest: 70 tests passed; branch coverage 83.05% (threshold 83%).
• Manual browser walkthrough recorded: /opt/cursor/artifacts/terminal_virtual_filesystem_walkthrough.mp4 showing pwd, ls, cd projects, prompt path updates, cat link-converter.txt, cat contact.txt, and ls --commands.