[Spec 05] Jump-to-flagged-region in UI

[fwright21]

Summary

Implement jump-to-flagged-region UX (Spec 05) for both single-clip and suite case review.

Scope

• Render flagged_regions list with severity and timestamp range.
• Add ▶ Jump behavior that seeks and plays the correct case audio element.
• Ensure jump works when metadata is not preloaded (wait for metadata as needed).
• Keep behavior consistent between single analysis and suite cards.

Acceptance Criteria

• Clicking jump seeks to the expected timestamp.
• No false seeks to end-of-clip for early timestamps.
• Missing timestamp entries render safely without jump controls.
• UI regression tests cover jump wiring.