Add terminal GitHub repository browser

[cursor]

Issue

Visitors can open Jakob's GitHub profile from the terminal, but they cannot discover and jump directly to specific repositories from the site. This makes the terminal emulation less useful for surfacing systems-programming projects and other GitHub work.

Proposed improvement

Add a terminal repository browser that merges curated project metadata with Jakob's live public GitHub repositories, making repos searchable and directly accessible from terminal commands.

Changes

• Added repository catalog helpers for merging curated projects with GitHub API repo data.
• Added repo [name-or-slug], repo --list, repo --lang C, repo --search term, and repos [filter] behavior.
• Kept repo with no arguments as a GitHub profile shortcut.
• Added githubOwner site config and README docs for the repository browser.
• Added unit tests for catalog merging, parsing, filtering, output formatting, and fallback paths.

Acceptance criteria

• repo --lang C lists systems-programming C repositories from the terminal.
• repo jakobs-ls-remake displays repo detail and opens the source repository.
• If the GitHub API is unavailable, curated repositories still render.

Verification

• pnpm check passed via pre-push hook (lint, format check, coverage, build).