feat: Enhanced Session View — follow actions, probability, and arrangement recording

[ChuxiJ]

Context

From DAW tech stack research: Ableton Live's Session View is the gold standard for live performance and improvisation. Our sessionStore already has scene launching, follow actions, and arrangement recording — but the UX and feature depth should match Ableton's maturity.

Bitwig's clip launcher adds unique modulation capabilities per clip. We can combine Ableton's workflow polish with our AI generation to create something neither has.

Goal

Deepen the Session View to be a compelling live performance and composition tool, with AI-enhanced clip generation.

Acceptance Criteria

• Follow action chains: next, previous, random, first, last, with probability weights
• Quantized launch: clips snap to bar/beat boundaries on trigger
• Per-clip tempo and time signature overrides
• Record session performance to arrangement view (capture mode)
• AI-fill: right-click empty slot → "Generate clip for this slot" using context from adjacent clips
• Scene chaining: auto-advance through scenes with configurable timing
• Visual feedback: playing/queued/recording states with animations
• MIDI controller mapping for scene/clip launch

Strategic Context

Industry benchmark: Ableton Session View, Bitwig Clip Launcher
Our advantage: AI can generate clips on-the-fly for empty slots
Builds on: sessionStore.ts, session components, generationPipeline

Part of: DAW Best Practices Research Series

[ChuxiJ]

Priority Update: P1 → P3

Enhancement that overlaps with existing issues #926, #1032, #1033, #1034. Deferred until core experience polish (P0/P1) is complete. Re-prioritized as part of Experience Polish Series.

---

Generated by Claude Code