Standalone binary via bun compile (no Bun install required)

[amaar-mc]

Currently users need Bun installed globally to run Wit. bun compile can produce a standalone binary that bundles the Bun runtime.

Challenges:

• WASM files (tree-sitter grammars) need to be embedded via Bun.embeddedFiles or shipped as sidecars
• Drizzle migration SQL files need to be bundled
• This was identified as a Phase 2+ concern in the original design

Impact: Removes the Bun dependency for end users. They'd just download a single binary.

# Goal
curl -fsSL https://github.com/amaar-mc/wit/releases/latest/download/wit-macos-arm64 -o /usr/local/bin/wit
chmod +x /usr/local/bin/wit
wit init