Restore Folder Studio review evidence surface

[cbusillo]

Summary

• Adds a concrete output review surface for Folder Studio with measured sample size, projected folder output, video draft, audio, subtitle, and review-media facts.
• Surfaces the side-by-side review download beside the decision actions and makes review media thumbnails directly openable.
• Wires previously dead Revise and Stop sample actions, removes duplicate artifact text, and makes the support Target panel reflect the active draft instead of contradicting it.

UX Evidence

• Browser-reviewed the live Terminator Season 2 folder route after sample completion.
• Two read-only UX critique agents independently flagged separated decision/evidence, hidden download, unwired Revise/Stop, duplicate artifacts, and contradictory target state; this PR implements the low-risk consensus fixes.
• Remaining larger design concern: the next pass should collapse decision and evidence into a single active review panel instead of stacking sections.

Validation

• bash scripts/pre-commit-check.sh
• JetBrains/PyCharm changed-files inspection: clean, 0 findings