Completes the self-contained flow:
- to-tickets: slice a spec too big for one PR into tracer-bullet tickets
  with declared blocking edges; publishes to tracker or local files.
  Graph orders the work, does not parallelise it.
- session-handoff: ephemeral session handoff to .scratch/handoffs/;
  records git state (branch/SHA/dirty/unpushed), references artifacts by
  path, guarantees the .gitignore entry, redacts secrets. Enforces
  state-not-decisions and the three-session promote-to-ADR rule (ADR 0002).

plugin.json + README + docs synced; version 0.2.0 -> 0.3.0.
Validated --strict; 9/9 skills wired, 9/9 docs pages.