flowjet 2.1.9 — refreshed builtin skills bundle

Changed

• Refreshed builtin skills bundle. Shipped two new research skills and
  retired a stale one: added autoresearch (an autonomous research loop with an
  orchestrator, scoring, and a security checklist) and oh-my-research (a
  structured evidence → synthesis pipeline with scripts and pattern presets),
  and removed the superseded research-bootstrap skill. The platonic-coding
  skill was reworked — its spec/IMPL/WORKFLOW references were tightened, a new
  specs-partition.md reference added, and the old coding-plan-template.md /
  impl-guide-template.md drafts dropped in favor of the consolidated template
  namespace. The top-level builtin_skills/README.md (a stale pointer) was
  removed; skills are still auto-registered via register_builtin_skill_root.