Data: Add Rust and Go language support

[cwklurks]

Is your feature request related to a problem? Please describe.
We currently support Python, Java, C++, and JS. We are missing modern systems languages.

Describe the solution you'd like

1. Update SupportedLanguage type in lib/snippets.ts.
2. Add a new section to data/leetcode-snippets.json for rust or go.
3. Add 5-10 standard algorithm snippets (e.g., Binary Search, DFS) for that language.

Note: Please ensure indentation in the JSON uses spaces/tabs consistently with the existing format.