0.13.2

Maintenance release for self-hosted Tartelet fleets.

• Waits for VM and runner cleanup before macOS terminates the app.
• Makes controller cancellation safe during launch.
• Sends SIGINT first so Tart can shut down VMs and networking cleanly.
• Tracks descendant process identity and uses an identity-checked SIGKILL fallback after the grace period.
• Adds a retry backoff after failed starts and promotes lifecycle failures to ERROR logs.
• Built from merged PR #2: #2

Known observability limitation: raw Tart stderr is not yet captured. This is an ad-hoc-signed internal build.