Replay: Add markdown export for Goal Story summaries

[smota]

Background & Problem Statement

Epic: #127

Replay should be shareable in PRs, issue comments, reviews, and postmortems without requiring every viewer to use the UI.

Proposed Solution

Add markdown export that summarizes goal, scope, key decisions, validation, review/gates, outcome, and follow-ups with evidence links.

Requirements

• Export compact summary and optional full timeline.
• Include evidence links and inferred/missing badges.
• Include privacy-safe content only.
• Output suitable for GitHub comments or docs.
• Do not include raw transcripts/prompts/tool inputs.

Acceptance criteria

• Export includes required AgentFlow sections.
• Export links to durable GitHub evidence.
• Export handles incomplete goals with explicit gaps.
• Snapshot tests cover merged and incomplete goal examples.

Test plan

• Markdown snapshot tests.
• Privacy redaction tests.
• Manual copy/paste check into GitHub markdown.

Workflow classification

Product/docs feature.

[github-actions]

Integrated into development by PR #133: #133

Merge commit: 823d2e784f61e11645d2902e35401134fe0b1bdc
Release/promotion to main is tracked separately.

[smota]

AgentFlow whole-model alignment

This issue was aligned with the current AgentFlow SDLC product model for screenshot/demo consistency.

• Product area: product:cockpit, product:docs
• Release assignment: v1.0.0 / release:v1.0.0
• Workflow state: Implemented on development; included in v1 release model.
• Compatibility rule: GitHub/CLI durable workflow remains authoritative; generated harness surfaces stay adapters only.
• Cockpit is treated as optional first-class Goal Command Center: package/release-gated, runtime opt-in, no unique state.

No implementation change is implied by this metadata-only alignment comment.