Add custom env var support to OpenCode integration

[Destreyf]

Summary

Adds an optional env parameter to OpencodeOptions that allows passing custom environment variables to the OpenCode process.

Use cases:

• OTEL telemetry (OTEL_EXPORTER_OTLP_ENDPOINT, OTEL_EXPORTER_OTLP_PROTOCOL)
• W3C distributed tracing (TRACEPARENT)
• Any other custom env vars users need

Example Usage

const { client, server } = await createOpencode(sandbox, {
  config: myConfig,
  env: {
    TRACEPARENT: "00-abc123-def456-01",
    OTEL_EXPORTER_OTLP_ENDPOINT: "http://127.0.0.1:4318",
  },
});

Custom env vars are merged with config-extracted variables (like API keys) and can override them if needed.

Changes

• Added env?: Record<string, string> to OpencodeOptions in types.ts
• Threaded env through ensureOpencodeServer() and startOpencodeServer()
• Added merge logic so custom env vars override config-extracted ones
• Updated JSDoc examples to show the new option
• Added example helper in examples/opencode/src/index.ts showing trace context propagation
• Added documentation in examples/opencode/README.md for the new feature
• Added unit tests for custom env vars and override behavior

Testing

• All 24 unit tests pass (22 existing + 2 new)
• TypeScript compilation passes
• Biome linting passes

[changeset-bot]

🦋 Changeset detected

Latest commit: dbe3390

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@cloudflare/sandbox	Minor

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