powerqueue v0.15.0

Added

• Execution projects: register multiple checkouts under [projects.<id>], enqueue
  with add --project, and reassign unstarted tasks with task project. One
  daemon shares slots and provider budgets while resolving setup, prompts,
  priority and cleanup per project. Existing tasks migrate to default; pinned
  checkouts and ownership checks protect retries, review and cleanup across
  restarts. doctor reports project configuration and binding problems.

Changed

• Testing: extend the Rust daemon model with project reassignment, independent
  policies, unavailable/moved checkouts, and stale SQLite launch claims. Extend
  Quint with execution-project ownership invariants and a finite model of the
  reassignment/launch race, including both models in the simulation checks.
• Testing: replace the Python Quint replay adapter with a Rust Cargo example,
  reusing application event types and preserving anonymized schedules, coverage
  reports, task-prefix cutoffs and invalid-schedule checks. Projection tests run
  in the Rust gate; advisory CI runs Quint checks and all three daemon traces.