feat(studio): add Edit Range toolbar with Copy to Agent

[miguel-heygen]

Summary

• Replace Split/Delete buttons with Edit Range toolbar
• Edit button opens a time-range selection on the timeline
• "Copy to Agent" exports the selected range as a prompt-ready description
• Range selection shows start/end times with drag handles

🤖 Generated with Claude Code

[miguel-heygen]

• refactor(studio): wire vite.config.ts to shared studio API module #115
• refactor(core): extract shared studio API module #113
• fix(core): strip template wrapper before linting composition files #111
• fix(cli): align render output naming and add WebM support to studioServer #109
• feat(studio): render queue, layout restructure, home page, hover preview #95
• feat(studio): add left sidebar with Compositions and Assets tabs #94
• feat(studio): add Edit Range toolbar with Copy to Agent #65 👈 (View in Graphite)
• refactor(studio): update layout, config, and remove agent activity tracking #64
• refactor(studio): improve Timeline, PlayerControls, and player hook #63
• main

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[vanceingalls]

Review: PR #65 — Edit Range Toolbar

Smart architectural decision — replacing ~400 lines of fragile split/delete code with agent handoff. The structured clipboard payload is well-designed for AI consumption.

Issues

[Important] `EditModal` has a local `formatTime` that shadows the shared utility. Shows `"2.5s"` format vs the shared `time.ts` `"0:02"` format. Time displays in the edit modal will look inconsistent with the player controls and timeline ruler.

[Important] `EditModal` reads `currentTime` from the store, but during playback the store's `currentTime` is only updated at end of playback or on seek — the RAF loop only updates `liveTime`. The time shown in the modal may be stale by several seconds if opened while playing.

**[Suggestion] `TimelineToolbar` shows `(E)` in the edit button title but doesn't register keyboard handlers. Zoom shortcuts (Cmd+/Cmd-) also not handled.

What's well done

• "Copy to Agent" with structured payload (time range, elements, prompt) is exactly the right pattern for agent collaboration
• Range sliders normalize with Math.min/Math.max to handle inverted ranges
• Clipboard fallback for older browsers
• Clean separation: toolbar triggers modal, modal builds context, agent does the mutation

[miguel-heygen]

Merge activity

• Mar 28, 7:59 AM UTC: A user started a stack merge that includes this pull request via Graphite.
• Mar 28, 8:00 AM UTC: Graphite couldn't merge this pull request because a downstack PR feat(studio): add TimelineClip and thumbnail components #62 failed to merge.
• Mar 28, 5:19 PM UTC: A user started a stack merge that includes this pull request via Graphite.
• Mar 28, 5:40 PM UTC: The Graphite merge of this pull request was cancelled.
• Mar 28, 7:50 PM UTC: @miguel-heygen merged this pull request with Graphite.