fix: stabilize Windows launcher supervision and Grok probe

[mouzhi]

Summary

• keep the npm launcher attached on Windows after the native Launcher reports ready, so command hosts cannot reap the managed Desktop/Controller process tree when the wrapper exits
• preserve the existing macOS/Linux behavior of returning immediately after readiness, and bound the startup handshake buffer while retaining split-marker detection
• include Grok in renderer-binding probe capabilities and status/selection validation

Validation

• npm run check
  • formatting, lint/boundaries, and TypeScript type checks passed
  • TypeScript: 158 test files passed, 1 skipped; 1330 tests passed, 15 skipped
  • Rust fmt, clippy, workspace tests, and doc tests passed
• generated-launcher behavior tests execute the emitted npm entry and verify:
  • Windows waits through ready and propagates the later native Launcher exit code
  • macOS/Linux return 0 at ready
  • a 1 MiB startup chunk plus a split ready marker is handled without cumulative buffering
• renderer probe tests directly accept a Grok selection and reject an unknown agent
• rebuilt and packed 0.3.3-pr.windows-launcher-grok-probe.2 Windows platform and meta packages

Runtime scope

No live Codex Desktop installation was replaced or restarted while preparing this PR. The changes were built and tested in an isolated worktree.

[chatgpt-codex-connector]

Codex usage limits have been reached for code reviews. Please check with the admins of this repo to increase the limits by adding credits.
Credits must be used to enable repository wide code reviews.