fix(studio,producer): post-merge regressions — fixes #1636, #1637, #1644

[miguel-heygen]

Summary

Fixes CI failures and open issues after the keyframe editing stack merge (#1605).

CI fix

• Test import: gsapDragCommit.test.ts imported commitGsapPositionFromDrag from gsapDragCommit but it was extracted to gsapDragPositionCommit

Fixes #1637 — crypto.randomUUID is not a function on plain HTTP

• Added generateId() helper with insecure-context fallback (Date.now()-Math.random()) for all 6 call sites across 5 files

Fixes #1636 — Live preview freezes after ~10s, playhead jumps to end

• clock.setDuration() was called every tick with a DOM-derived duration. A transient shorter read (from sanitizeCompositionDurationAttributes stripping sub-comp attrs mid-tick) would shrink the duration → reachedEnd() fires → playhead jumps to end
• Fix: never shrink duration while playing — only grow or hold steady

Fixes #1644 — ENOTEMPTY race on worker directory cleanup

• Chrome worker processes write GPU cache/crash dumps after the render completes. rmSync({recursive: true}) walks the tree, removes files, then rmdir — but Chrome writes a new file between the walk and the rmdir
• Fix: add maxRetries: 3, retryDelay: 100 to rmSync in the three cleanup paths (orchestrator, distributed chunk, shared cleanup helper)

Enable keyframes

• Flipped STUDIO_KEYFRAMES_ENABLED default from false to true

Test plan

• bun test packages/studio/src/hooks/gsapDragCommit.test.ts — 12/12 pass
• Studio preview works over plain HTTP (no crypto crash)
• Continuous playback >10s does not freeze
• Multi-worker renders clean up without ENOTEMPTY errors
• Keyframe diamonds visible in timeline without env flag