feat(release-management): add verify-rc live checklist pane Claude Code mod (part of #1497) #2006

What should happen

release-verify-rc should display an interactive live verification checklist in a persistent terminal review pane (ui.render Pane) when running under Claude Code, updating each verification check (signatures, checksums, RAT headers, NOTICE/LICENSE, prohibited binaries, symlinks, version manifests, and reproducibility) with real-time status indicators as steps complete.

Why

During release candidate verification in plugins/magpie-release-management/skills/verify-rc/SKILL.md, verifying an Apache Release Candidate executes 8–9 distinct mechanical checks. Currently, progress and verdicts are reported exclusively via sequential conversational text turns, which clutters the LLM context window and gives the Release Manager or voter no persistent dashboard showing what has passed, what is running, and what remains.

As identified in #1497:

release-verify-rc checklist pane: One row per check, filled in as the steps finish.

Providing a dedicated, additive Claude Code mod pane gives Release Managers and voters a zero-token visual status dashboard while strictly preserving vendor-neutral text fallbacks across non-Claude harnesses.

Which layer

Other / unsure

Boundary conditions (optional)

• Vendor Neutrality: When running on non-Claude harnesses (Codex, Antigravity, Cursor, CI) or when mods are disabled/unsupported, release-verify-rc must continue operating via standard sequential CLI output without error.
• Fail-Open Execution: Intercepting commands (release-config preflight, release-verify, and RAT checks) via tool.call must unconditionally invoke next(e) so tool execution is never blocked or gated.
• Dual Execution Modes: The mod must handle both individual subcommand runs (release-verify signatures, release-verify checksums, etc.) and the bundled release-verify all execution cleanly.
• Step Status Fidelity: Steps should visually distinguish between pending, running, passed, failed, warning, and skipped (e.g. when --skip-repro is passed).
• Session Hygiene: The state atom should reset on session start and initialize freshly when a new RC pre-flight check begins.

Out of scope (optional)

• Changing or bypassing ASF voter obligations: mechanical verification remains an aid, not an autonomous vote (Golden Rule 4).
• Modifying underlying CLI logic in tools/release-verify/ or tools/release-management/.
• Private key handling or automatic GPG signing (Golden Rule 5).

References (optional)

• Part of Explore Claude Code mods across the skill families #1497 (Explore Claude Code mods across the skill families)
• docs/when-to-use-mods.md
• plugins/magpie-release-management/skills/verify-rc/SKILL.md
• tools/release-verify/README.md