v0.1.1 — Enforce concurrent fan-out limits

Fixes the per-session child limit during concurrent fan-outs.

• Atomically reserve the complete fan-out before starting children, keeping concurrent calls within the 36-child limit.
• Release unused reservations after partial startup failures, while preserving the cumulative count of children already started.
• Add concurrency and partial-failure regressions, GitHub CI, and a publish-time test gate.

Validation: all 10 smoke checks passed. The attached npm tarball installs and imports in a clean directory.

The attached tarball is ready for use. npm publication is pending maintainer authentication; this GitHub release does not confirm npm availability.