Add Bug Receipt evidence-gated debugging skill (#2628)

* Add Bug Receipt agent skill

* Refine Bug Receipt proof boundaries

docs/README.skills.md

@@ -92,6 +92,7 @@ See [CONTRIBUTING.md](../CONTRIBUTING.md#adding-skills) for guidelines on how to
 | [breakdown-feature-prd](../skills/breakdown-feature-prd/SKILL.md)<br />`gh skills install github/awesome-copilot breakdown-feature-prd` | Prompt for creating Product Requirements Documents (PRDs) for new features, based on an Epic. | None |
 | [breakdown-plan](../skills/breakdown-plan/SKILL.md)<br />`gh skills install github/awesome-copilot breakdown-plan` | Issue Planning and Automation prompt that generates comprehensive project plans with Epic > Feature > Story/Enabler > Test hierarchy, dependencies, priorities, and automated tracking. | None |
 | [breakdown-test](../skills/breakdown-test/SKILL.md)<br />`gh skills install github/awesome-copilot breakdown-test` | Test Planning and Quality Assurance prompt that generates comprehensive test strategies, task breakdowns, and quality validation plans for GitHub projects. | None |
+| [bug-receipt](../skills/bug-receipt/SKILL.md)<br />`gh skills install github/awesome-copilot bug-receipt` | Fix software defects with an auditable proof receipt: reproduce, trace root cause, repair, verify, and report VERIFIED, PARTIAL, or BLOCKED. Use for bug fixes and regressions. | `assets/receipt.template.json`<br />`references/receipt-contract.md`<br />`references/receipt.schema.json`<br />`scripts/validate-receipt.mjs` |
 | [bug-reproduction-brief](../skills/bug-reproduction-brief/SKILL.md)<br />`gh skills install github/awesome-copilot bug-reproduction-brief` | Turn a vague, intermittent, or environment-specific bug report into a minimal evidence-backed reproduction before proposing a fix. | None |
 | [build-evidence-map](../skills/build-evidence-map/SKILL.md)<br />`gh skills install github/awesome-copilot build-evidence-map` | Build an auditable evidence map for a contested technical choice, research synthesis, proposal review, or consequential decision. Use when Copilot must preserve supporting, contradicting, qualifying, and missing evidence with exact source regions instead of collapsing disagreement into prose. | `references/evidence-ladder.md`<br />`references/map-schema.md`<br />`scripts/contract.mjs`<br />`scripts/validate.mjs` |
 | [centos-linux-triage](../skills/centos-linux-triage/SKILL.md)<br />`gh skills install github/awesome-copilot centos-linux-triage` | Triage and resolve CentOS issues using RHEL-compatible tooling, SELinux-aware practices, and firewalld. | None |