skill: make the peltier skill consumable across agent harnesses

The SKILL.md Agent Skills standard (agentskills.io) is now read natively by
Codex, Copilot, VS Code, Cursor, Gemini CLI, opencode, Goose, Amp, Zed,
Factory, and ZeroClaw — so the portable move is not per-harness adapter
files (forked content that drifts) but one canonical skill placed where
each harness actually looks.

- Spec-compliant frontmatter: license, compatibility (the Linux-only
  measurement story, stated up front), version/author/tags top-level
  (ZeroClaw's runtime reads those; the spec ignores unknown fields).
  reference/ renamed to references/ per the spec's conventional layout.
- .agents/skills/peltier/ mirror: the cross-tool convergence path (Codex,
  Zed, Cursor, Gemini CLI, Copilot, opencode, Goose, Amp). Byte-identical
  to the .claude canonical, enforced by CI — drift between the two copies
  is a red build, not a footnote.
- AGENTS.md at the repo root for the ~20 harnesses that read it (Claude
  Code does not; CLAUDE.md remains its file). Deliberately thin: it points
  at CLAUDE.md and the skill instead of restating rules.
- scripts/install-skill.sh: stamps a consumer repo at both discovery paths
  (--layout claude|agents|both), or emits a script-less --zeroclaw-variant.
  ZeroClaw's skill security policy blocks script files by default
  (skills.allow_scripts off) — its audit rejected the full skill and passes
  the variant, verified against the real zeroclaw binary. The variant loses
  nothing: preflight.sh still exists exactly once, in the peltier checkout
  the skill already requires, and SKILL.md now documents running it from
  there. Re-implementing preflight inline is named as a refusal condition.
- CI (skill-preflight): frontmatter upgraded to a full Agent Skills spec
  conformance check on BOTH copies (name rules, dir match, description and
  body limits, metadata string-map), plus mirror equality and a functional
  installer test (both layouts identical to canonical, variant carries no
  scripts/, nonexistent target refused).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

.claude/skills/peltier/SKILL.md

@@ -1,6 +1,14 @@
 ---
 name: peltier
 description: "Prove a performance change is real — or refuse to claim it. Use when optimizing code for speed, verifying a claimed speedup ('is this actually faster?', 'did my optimization work?'), checking for a performance regression ('did this PR make things slower?'), or comparing the performance of two implementations. Runs peltier's trust layer — equivalence gates, A/A environment calibration, interleaved A/B with bootstrap confidence intervals. Never reports a naked percentage and never claims a win that is not statistically significant. Do NOT use for correctness-only work."
+license: "GPL-3.0-or-later"
+compatibility: "Needs a peltier checkout (https://github.com/bdbrown4/peltier.io; set PELTIER_HOME) with cargo to build bench-runner. Measurement requires a Linux/POSIX host; on unsupported hosts the skill refuses to produce numbers rather than degrade."
+version: "1.1.0"
+author: "peltier.io (Ben Brown)"
+tags: ["performance", "benchmarking", "statistics", "verification"]
+metadata:
+  homepage: "https://bdbrown4.github.io/peltier.io/"
+  source: "https://github.com/bdbrown4/peltier.io"
 ---
 
 # peltier — prove it, or claim nothing
@@ -22,6 +30,16 @@ plugin, or copied into another project):
 
     sh <skill-dir>/scripts/preflight.sh
 
+Some harnesses block script files inside skills, so your installation may
+carry no `scripts/` directory. The script still exists exactly once — in the
+peltier checkout this skill drives (which you need anyway; it is where
+`bench-runner` lives). Run it from there:
+
+    sh "$PELTIER_HOME/.claude/skills/peltier/scripts/preflight.sh"
+
+Never transcribe or re-implement the preflight logic inline; if you cannot
+locate a checkout to run it from, that IS a preflight refusal — report it.
+
 It locates the trust layer, builds the real `bench-runner`, and checks this
 host can run it. `STATUS=ok` does **not** mean the host can measure your
 change — only the A/A self-test decides that.
@@ -37,8 +55,8 @@ copy of the math is a second thing that can lie.
 
 | Mode | Use when | Read |
 |---|---|---|
-| **verify** | You have a baseline and a candidate — any repo, any language. | [reference/verify.md](reference/verify.md) |
-| **attempt** | You are inside a peltier checkout and want the full loop: profile → hypothesize → patch → gated verdict → ledger row. | [reference/attempt.md](reference/attempt.md) |
+| **verify** | You have a baseline and a candidate — any repo, any language. | [references/verify.md](references/verify.md) |
+| **attempt** | You are inside a peltier checkout and want the full loop: profile → hypothesize → patch → gated verdict → ledger row. | [references/attempt.md](references/attempt.md) |
 
 Default to **verify**. It is the portable one, and it is what almost every
 request actually wants.