v4.1.0: three more agents

v4.1.0: three more agents

Same lazy senior dev, three new places to put him. No change to the rules or the
benchmark numbers. This release is reach, not behavior.

New adapters

• Codex (#7): full plugin with a marketplace manifest, lifecycle hooks, and a
  shared runtime that keeps the Claude path byte-identical. Invoke as @ponytail,
  @ponytail-review, @ponytail-help.
• Pi (#1): a Pi extension with /ponytail mode control, per-session
  persistence, and system-prompt injection. Install with
  pi install git:github.com/DietrichGebert/ponytail.
• Kiro (#6): a drop-in steering file at .kiro/steering/ponytail.md.

Eight hosts now: Claude Code, Codex, Pi, Cursor, Windsurf, Cline, Copilot, Kiro.

Tooling and docs

• Rule-copy drift check (#3, #9): node scripts/check-rule-copies.js keeps
  every adapter copy aligned with AGENTS.md and guards the SKILL.md source against
  silently losing a rule.
• Agent portability doc (#2, #10): one table mapping each host to its files.
• Cross-platform fix for the hook compatibility test (Windows os.homedir).

Under the hood

The hooks were factored into a shared runtime (ponytail-runtime.js) and
instruction builder (ponytail-instructions.js), so Claude, Codex, and Pi load
the same rules instead of each duplicating the logic. Every adapter is
unit-tested; the Codex and Pi extension APIs were verified against their official
docs.

Full changelog: v4.0.0...v4.1.0