Add type-specific outcome evaluators for create_issue, add_comment, and add_labels

[Copilot]

This PR replaces existence-based outcome classification for create_issue, add_comment, and add_labels with dedicated evaluators that use engagement/lifecycle signals and persisted label state. It also adds branch-complete coverage for accepted/rejected/pending/unknown outcomes across these types.

• Outcome evaluation: dedicated classifiers

  • actions/setup/js/evaluate_outcomes.cjs now routes create_issue, add_comment, and add_labels through type-specific evaluators.
  • create_issue now classifies based on engagement and closure behavior:
    • accepted (strong): open + merged PR/commit/closing reference
    • accepted (medium): open + non-author comment/reaction
    • rejected (strong): immediate close by non-author (windowed)
    • rejected (medium): closed with no activity
    • pending/unknown fallbacks
  • add_comment now classifies based on comment lifecycle and thread activity:
    • rejected (strong): comment deleted
    • accepted (strong): reacted/replied/quoted
    • accepted (medium): later thread activity
    • pending/unknown fallbacks
  • add_labels now evaluates retention using before-state + added labels with a retention window:
    • accepted (strong): added labels retained
    • rejected (strong): removed by non-author within retention logic
    • pending before window elapses
    • unknown when before-state is unavailable

• Manifest/data model updates for add_labels

  • actions/setup/js/add_labels.cjs captures labelsBefore before label mutation.
  • actions/setup/js/safe_output_manifest.cjs persists labelsBefore and labelsAdded for downstream evaluation.

• Focused test coverage for outcome branches

  • Added actions/setup/js/evaluate_outcomes.test.cjs to cover outcome branches for all three evaluators.
  • Updated actions/setup/js/safe_output_manifest.test.cjs to assert new label metadata extraction.

if (item.type === "create_issue") {
  return evaluateCreateIssue(item, itemRepo, timestamp, out, apiGet, nowMs);
}
if (item.type === "add_comment") {
  return evaluateAddComment(item, itemRepo, timestamp, out, apiGet, nowMs);
}
if (item.type === "add_labels") {
  return evaluateAddLabels(item, itemRepo, timestamp, out, apiGet, nowMs);
}