[Audit/Meta] Sprint-2 roll-up (P0 forensic replay)

[Delqhi]

Roll-up tracking Sprint-2 P0 items

Sub-issues:

• feat(replay): per-session HAR export (full request/response bodies) #9 per-session HAR export
• feat(replay): Playwright trace.zip per session #10 Playwright trace.zip per session
• feat(replay): screenshot timeline (every action + on failure) #11 screenshot timeline
• feat(replay): single-zip bundle exporter (unmask bundle <session>) #12 single-zip bundle exporter (unmask bundle <session>)

This is our hero feature vs Browser-Use / Stagehand / Skyvern. Must ship complete + documented.