feat(studio): timeline collision and placement model#2279
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What: new pure module timelineCollision — zone-aware drop placement (clampTrackToZone, resolveZoneDropPlacement, resolveInsertRow, resolvePlacement, lane/overlap predicates) with its full test suite. Why: the no-overlap core of the NLE clip-drag engine; plain functions, no DOM, no React, no store writes. How: new files only; type-only imports from the existing playerStore. First runtime consumer arrives with the drag-engine PRs. Test plan: bunx vitest run timelineCollision.test.ts; tsc --noEmit; fallow audit clean (all exports test-consumed).
What: new pure module timelineSnapping — snap-target collection and pixel-threshold time snapping (collectTimelineSnapTargets, snapTimelineTime, snapMoveToTargets) with tests. Why: the magnet math for clip drags/trims, reviewable standalone. How: new files only; type-only playerStore imports; consumers land with the drag engine. Test plan: bunx vitest run timelineSnapping.test.ts; tsc --noEmit; fallow audit clean.
What: new pure module timelineMultiDragPreview — group-drag passenger offsets and clamped group deltas (isMultiDragActive, multiDragDeltaSeconds, multiDragPassengerOffsetPx, clampGroupMoveDelta) with tests. Why: the group-drag math, standalone and DOM-free. How: new files only; consumed later by TimelineLanes. Test plan: bunx vitest run timelineMultiDragPreview.test.ts; tsc --noEmit; fallow audit clean.
What: new pure module timelineStackingSync — lane order ↔ z-index reconciliation (laneIsAbove, computeStackingPatches) with tests. Why: the single source of truth for how timeline lane order maps to canvas stacking; the ordering rules and tie-breaks live here. How: new files only; consumed later by timelineZones and the stacking-sync hook. Test plan: bunx vitest run timelineStackingSync.test.ts; tsc --noEmit; fallow audit clean.
What: new pure module timelineZones — visual/audio track-zone classification (classifyZone) and normalizeToZones, which re-packs lanes into zone-consistent rows; tests cover the stacking/zones interaction. Why: completes the z-model started in the stacking-sync PR. How: new files; consumes isAudioTimelineElement (leaf-helpers PR) and computeStackingPatches (stacking-sync PR); type-only playerStore imports. Test plan: bunx vitest run timelineZones.test.ts; tsc --noEmit; fallow audit clean.
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This was referenced Jul 12, 2026
This was referenced Jul 12, 2026
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How
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