v0.16.3

Added

• Added task lifecycle duplicate diagnostics to millrace doctor; workspaces
  now report duplicate_task_lifecycle_state when the same task id appears in
  more than one task lifecycle directory.

Fixed

• Same-id execution continuations that reach tasks/done/ now safely retire a
  same-root stale predecessor from tasks/blocked/ into
  tasks/blocked/superseded/, preserving an audit record while unblocking
  closure readiness.
• Manager guidance now explicitly avoids writing a task card whose Task-ID
  already exists in task lifecycle state unless the runtime has requeued the
  original task.