fix: make spawn() work when host is an Electron main process

[Copilot]

In an Electron main process, process.execPath is the Electron binary. Spawning the bundled .js CLI with it fails two ways: bare spawn triggers single-instance lock → clean exit → misleading CLI server exited unexpectedly with code 0; with ELECTRON_RUN_AS_NODE=1 alone, process.versions.electron is still set in the child, Commander picks Electron argv parsing, and --headless is misclassified as a positional arg → error: too many arguments.

Changes

• applyElectronSpawnEnv(env, isJsFile) (client.ts) — new @internal helper; when process.versions.electron !== undefined and the CLI is a .js file, injects ELECTRON_RUN_AS_NODE=1 and COPILOT_CLI_RUN_AS_NODE=1 via ??= (caller values are never overwritten). No-ops in all non-Electron hosts.

• getNodeExecPath(override?) — accepts an optional path override; exported @internal for testability.

• CopilotClientOptions.nodeExecPath?: string (types.ts) — escape hatch for Electron apps that bundle a real Node binary, bypassing the env-var injection entirely:

  const client = new CopilotClient({
      nodeExecPath: process.env.MY_APP_NODE_PATH ?? "node",
  });

• startCLIServer() — wired to call applyElectronSpawnEnv before spawn and pass options.nodeExecPath to getNodeExecPath.

• 6 new unit tests covering injection, no-overwrite, non-.js skip, non-Electron no-op, override, and option storage.

• README — new "Electron usage" section documenting both failure modes and both fixes.

• CHANGELOG — [Unreleased] Fixed entry.

[Copilot]

Pull request overview

Fixes a startup failure when the Node.js SDK is hosted inside an Electron main process, where process.execPath points at the Electron binary and spawning the bundled .js CLI either silently exits (single-instance lock) or trips Commander's Electron argv parsing on --headless.

Changes:

• New @internal helper applyElectronSpawnEnv() injects ELECTRON_RUN_AS_NODE=1 and COPILOT_CLI_RUN_AS_NODE=1 (via ??=) for .js CLIs when process.versions.electron is defined, and getNodeExecPath() now accepts an optional override.
• New public CopilotClientOptions.nodeExecPath escape hatch for apps that bundle a real Node binary; wired through to the .js spawn branch in startCLIServer().
• Documentation (README "Electron Usage" section, CHANGELOG Unreleased entry) and 6 unit tests covering injection, no-overwrite, non-.js, non-Electron, override, and option storage.

Show a summary per file

File	Description
nodejs/src/client.ts	Adds applyElectronSpawnEnv, extends getNodeExecPath with override, stores nodeExecPath option, and uses both in the .js spawn branch.
nodejs/src/types.ts	Adds nodeExecPath?: string to CopilotClientOptions with JSDoc explaining the Electron use case.
nodejs/test/client.test.ts	New Electron spawn environment describe block exercising helper behavior and option storage.
nodejs/README.md	New "Electron Usage" section documenting failure modes, automatic fix, and nodeExecPath escape hatch.
CHANGELOG.md	Adds an [Unreleased] entry describing the fix and new option.

Copilot's findings

• Files reviewed: 5/5 changed files
• Comments generated: 1

[Copilot]

Addressed in 9480efeb: removed the manual [Unreleased] CHANGELOG entry so release notes remain generator-managed.