chore: relicense GPL-3.0-or-later -> MIT

Relicensed to make sharing and consumption frictionless — the skill is
meant to be dropped into arbitrary client repos, and MIT removes every
question a legal department would ask about that.

Clean to do unilaterally: git shortlog shows no third-party human
contributors (Ben Brown, Claude co-authoring Ben's sessions, and two
copilot-swe-agent[bot] workflow commits made at Ben's direction).

All living license surfaces swapped in lockstep: LICENSE (MIT text,
copyright 2026 Ben Brown), Cargo.toml workspace license, README, and the
skill frontmatter in both copies (.claude + .agents mirror, regenerated
byte-identical). Historical documents in results/ are records and keep
whatever they said at the time. Prior releases/clones under GPL-3.0
remain validly GPL-licensed at those commits, as always.

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

.agents/skills/peltier/SKILL.md

@@ -1,7 +1,7 @@
 ---
 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"
+license: "MIT"
 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)"