Contributing guide references `bun lint` script that doesn't exist

[marmarmo]

Bug description

The contributing guide instructs contributors to run bun lint, but the lint script is not defined in the root package.json. Attempting to run it results in the following error:
error: Script not found "lint"

This creates confusion for new contributors who follow the documented setup process and assume something is broken locally.

If the intended linting tool is Biome, consider either:

• Adding a lint script to package.json (e.g. "lint": "bunx biome check .") e.g.:,

"scripts": {
  "lint": "bunx biome check ."
}

• Update the README to remove or correct the reference to bun lint if it is no longer maintained
• Add a bun lint step to the GitHub Actions workflow (ci.yaml), alongside other steps like bun format:check, bun typecheck, etc., to ensure consistency and catch issues automatically in PRs

Let me know if you’d prefer a quick PR to resolve this — happy to help.

How to reproduce

1. Clone the Repository
2. Run bun install
3. Run bun link as instructed in the README.md here

Expected: Runs linting process
Actual: Fails with Script not found "lint"

Additional context

• Environment: bun v1.2.x, node v20.x (via nvm use)
• This is unrelated to the CI-only FontAwesome issues described elsewhere
• Formatting via bun format works as expected — this is specifically about the non-existent lint script
• Searched both the root and sub-package package.json files (e.g., @gitbook/cache-do) — none define a lint script
• The CI config (ci.yaml) also does not run bun lint, suggesting it was either deprecated or never added