fix: tools.env Go 1.27 tooling pins (golangci v2.13.1 + errcheck v1.20.0)

[bborbe]

Bump tools.env pins to canonical (matches go-skeleton): golangci-lint v2.13.1 (fixes Go 1.27 stdlib export-data mismatch; v2.12.2/v2.11.4 broken) and errcheck v1.20.0 (v1.10.0 fails with 'package without types' under Go 1.27). Unblocks the update-go precommit gate.

[ben-s-pull-request-reviewer]

Consolidated Report

Must Fix (Critical): None.

Should Fix (Important):

• CHANGELOG.md:1 — CHANGELOG.md has no ## Unreleased bullet. This repo uses autoRelease: true; the release agent promotes ## Unreleased bullets post-merge. Without a bullet, no version ships for this change. Add a conventional-prefixed bullet (e.g., - fix: bump errcheck to v1.20.0 for Go 1.27 compatibility). (rule: changelog/unreleased-entry-required)

Nice to Have (Optional): None.

---

Selector Mode Traceability:

• Candidates: 0 judgment rules matched by Step 4b-i glob filter (no *.go, go.mod, agents/**, commands/**, skills/**, or @commits triggers match tools.env)
• Applicable: 0 rules selected by Step 4c-sel
• Skipped: N/A — no candidates

---

{
  "verdict": "request-changes",
  "summary": "The ERRCHECK_VERSION bump from v1.10.0 to v1.20.0 is correct and consistent with golangci-lint v2.13.1 for Go 1.27, but the CHANGELOG.md is missing a ## Unreleased bullet — the autoRelease agent has nothing to promote post-merge, so no version will ship for this change.",
  "comments": [
    {
      "file": "CHANGELOG.md",
      "line": 1,
      "severity": "major",
      "message": "CHANGELOG.md has no ## Unreleased bullet. This repo is autoRelease=true; the release agent promotes ## Unreleased bullets post-merge. Without a bullet, no version ships for this change. Add a conventional-prefixed bullet under ## Unreleased (e.g., \"- fix: bump errcheck to v1.20.0 for Go 1.27 compatibility\")."
    }
  ],
  "concerns_addressed": [
    "correctness: ERRCHECK_VERSION v1.20.0 is the correct version for golangci-lint v2.13.1 / Go 1.27 — addressed, verified by cross-referencing tools.env canonical version pins"
  ]
}

superseded by new automated review

[ben-s-pull-request-reviewer]

All four versions align at 0.116.5. No issues.

---

Consolidated Report

Must Fix (Critical): None.

Should Fix (Important): None.

Nice to Have (Optional): None.

Notes:

• tools.env: ERRCHECK_VERSION bumped v1.10.0 → v1.20.0 for Go 1.27 compatibility. Correct pin, no issues.
• CHANGELOG.md: Added ## Unreleased section with the single fix bullet. Format follows existing conventions. No issues.
• Version alignment across all four files (CHANGELOG.md, plugin.json ×2, marketplace.json ×2) confirmed at 0.116.5 — no drift introduced.
• This is a tools-only bump; binary-relevant files (go.mod, .go sources) unchanged, so no scenario run required per the skip rule.

Selector mode — no adjudication needed. The diff touches only tools.env and CHANGELOG.md — neither matches any rule's file-extension or path trigger. Step 4 mechanical funnel and all LLM-judged rules are a no-op for this changeset.

{
  "verdict": "approve",
  "summary": "Minimal, correct tooling bump: errcheck v1.10.0 → v1.20.0 for Go 1.27 compatibility, with a clean CHANGELOG entry. No correctness, security, or architectural concerns. Version alignment verified.",
  "comments": [],
  "concerns_addressed": []
}