fix: ReferenceError: require is not defined in binary wrapper (Node.js 25+ / ESM) #22769

Description

In Node.js v25 and later, when a package's package.json contains "type": "module", all files are treated as ES modules. The current binary wrapper script (packages/opencode/bin/opencode) uses CommonJS require statements, which leads to a ReferenceError: require is not defined.

Additionally, in development environments where platform-specific binaries are not yet installed in node_modules, the wrapper fails to find the locally built binary in the dist folder.

OpenCode version

1.4.6 (current dev)

Steps to reproduce

1. Use Node.js v25.9.0 or later.
2. Run opencode command from the monorepo root or after a local build.
3. Observe the ReferenceError: require is not defined error.

Operating System

Windows 11 (Node.js v25.9.0)

Suggested Fix

• Convert the binary wrapper script (packages/opencode/bin/opencode) to use ESM import statements.
• Use fileURLToPath(import.meta.url) to correctly derive __filename and __dirname in an ESM context.
• Update the findBinary function to also search in the dist directory to support local development in monorepo environments.