[codex] keep direct CLI serve alive for Claude MCP

[stevenobiajulu]

What changed

The direct node .../dist/cli.js serve entrypoint now routes through a small runCliDirect() adapter that sets process.exitCode on success instead of calling process.exit(code) immediately.

A regression test was added to verify the direct serve path does not force-process-exit after the MCP stdio transport starts.

Why

Claude MCP health checks were failing when pointed directly at packages/email-mcp/dist/cli.js serve from the main checkout.

Root cause: the direct CLI auto-run path awaited runCli() and then unconditionally called process.exit(code). For serve, runCli() resolves after stdio transport setup, so the process exited right after startup and before Claude could complete its handshake.

Impact

This makes the main checkout usable as a direct Claude MCP runtime target without relying on a separate wrapper or alternate runtime worktree.

Validation

• npm run test:run -w @usejunior/email-mcp
• npm run build -w @usejunior/email-mcp
• claude mcp get email-agent-mcp-worktree-test -> Status: ✓ Connected
• manual runtime check: node packages/email-mcp/dist/cli.js serve stayed alive after startup

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ All tests successful. No failed tests found.

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