Pi Workflows 0.15.0

Pi Workflows 0.15.0 moves production workflow execution into one package-owned, on-demand host process.

• Run workflow and controller code in supervised child processes instead of the origin Pi process.
• Add a versioned local client, host, and worker protocol with strict validation and bounded messages.
• Keep one global workflow host as the normal durable-state writer, with atomic host lifecycle, stale-run cancellation, typed claim loss, and exact-token lease renewal.
• Persist origin-session interaction requests so workflow prompts and visible steps survive Pi restarts and resume in the correct session.
• Recover external effects through durable intent and receipt records. Effects with uncertain outcomes become ambiguous and require explicit operator recovery; this release does not claim exactly-once delivery.
• Remove embedded production workflow execution. There is one selectable production runtime after this alpha hard cut.
• Expand real-Pi end-to-end coverage for host execution, durable restart interaction, controller reconciliation, package discovery, status privacy, and Herdr integration.

This alpha release changes SQLite schema version 1 in place. Existing incompatible state is not migrated or changed. Back up and move state.sqlite together with its -wal and -shm files, then start Pi Workflows to create new state.