feat(skills): add release-readiness skill for ship-readiness assessment

PDE C-arm sweep flagged T22 (assess if a repo is ready to ship) as a
catalog gap — no skill scoped this read-only verdict workflow, so the
model thrashed 36 turns across 10 unrelated skills hunting for the
right tool surface.

Add release-readiness gating get_latest_release, list_commits,
search_pull_requests, list_issues, and actions_list (the multi-method
Actions tool; the body references its list_workflow_runs method
explicitly). Body sequences last-tag -> commits-since -> merged-PRs
-> open-blockers -> CI-green and produces an explicit verdict.

Bumps the skill count assertion from 27 to 28.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: asdfg-zxcvb

pkg/github/skill_resources.go

@@ -51,6 +51,7 @@ func allSkills() []skillDefinition {
 		skillDelegateCopilot(),
 		skillDiscoverGitHub(),
 		skillShareSnippet(),
+		skillReleaseReadiness(),
 	}
 }
 
@@ -491,6 +492,21 @@ func skillShareSnippet() skillDefinition {
 	}
 }
 
+func skillReleaseReadiness() skillDefinition {
+	return skillDefinition{
+		name:        "release-readiness",
+		description: "Assess whether a repository is ready to ship a release. Use when checking release readiness, deciding if it's safe to ship, reviewing recent commits since the last tag, hunting for open release-blocker issues, confirming CI is green on the release branch, or auditing merged PRs in the release window.",
+		allowedTools: []string{
+			"get_latest_release",
+			"list_commits",
+			"search_pull_requests",
+			"list_issues",
+			"actions_list",
+		},
+		body: "# Assess Release Readiness\n\nDecide whether a repository is ready to ship a release. This is a read-only checklist — produce a verdict, not a release.\n\n## Available Tools\n- `get_latest_release` — find the previous version tag\n- `list_commits` — commits on the release branch since that tag\n- `search_pull_requests` — merged PRs in the release window\n- `list_issues` — open issues, filterable by label\n- `actions_list` — recent workflow runs (use `method: list_workflow_runs`)\n\n## Workflow\n1. `get_latest_release` to find the last shipped tag and its date.\n2. `list_commits` on the release branch since that tag — confirm there's anything new to ship.\n3. `search_pull_requests` with `is:pr is:merged base:<branch> merged:>=<tag-date>` to inventory PRs in the window. Note any without release-relevant labels.\n4. `list_issues` with `state: OPEN` and the repo's release-blocker label (e.g. `release-blocker`, `priority:critical`). Any open blocker means not ready.\n5. `actions_list` with `method: list_workflow_runs` filtered to the release branch and the most recent commit — every required workflow run must be `success`.\n\n## Verdict\nReady when all of these are true: commits exist since the last tag, no open release-blocker issues, latest CI green on the release branch's HEAD. Otherwise call out exactly which gate failed and what would unblock it.\n",
+	}
+}
+
 // buildSkillContent builds the full SKILL.md content with YAML frontmatter.
 func buildSkillContent(skill skillDefinition) string {
 	var b strings.Builder

pkg/github/skill_resources_test.go

@@ -80,5 +80,5 @@ func TestRegisterSkillResources(t *testing.T) {
 
 	// Verify the expected number of skills were registered by counting definitions
 	skills := allSkills()
-	assert.Equal(t, 27, len(skills), "expected 27 workflow-oriented skills")
+	assert.Equal(t, 28, len(skills), "expected 28 workflow-oriented skills")
 }