Route WSL Lavish sessions through Windows runtime

[Ikha14]

Summary

• route WSL Lavish lifecycle operations through one Windows runtime and state store
• preserve paths and argv, including empty and stop-style arguments across PowerShell 5.1
• retain native non-WSL behavior and deterministic prerequisite failures

Tests

• bash tests/fm-lavish-route.test.sh
• bash tests/fm-lavish-windows-argv.test.sh

[greptile-apps]

Confidence Score: 4/5

The PR should not merge until a failed legacy poll upgrade preserves or restores the prior registration instead of silently disabling board supervision.

The upgrade path stops and deletes the existing poll before its replacement is durably published, so a realistic registration failure leaves captain answers without a supervised poll.

Files Needing Attention: bin/fm-procevent-lavish.sh

_{Reviews (1): Last reviewed commit: "Fix PowerShell empty Lavish arguments" | Re-trigger Greptile}

[greptile-apps]

Legacy poll registration is lost

When replacement registration fails after a legacy source is retired, this upgrade deletes the old source and stops its runner while restoring only the answer binding, causing subsequent board answers to remain unsupervised.

[Ikha14]

Superseded by the clean replacement PR #2833, which reconstructs the eight accepted commits and fixes the Greptile-reported legacy registration rollback defect.