feat: implement Ableton Live-style DAW layout

Major UX refactor to match professional DAW workflows (Ableton/Bitwig):

**Layout Changes:**
- Removed sidebar completely
- Track actions moved to header toolbar (Add/Import/Clear All)
- Each track now shows its own devices/effects in the track strip
- Master section moved to bottom footer area
- Full-width waveform display

**Track Strip (left panel):**
- Track name (editable inline)
- Color indicator
- Collapse/Solo/Mute/Delete buttons
- Volume slider with percentage
- Pan slider with L/C/R indicator
- Collapsible "Devices" section showing track effects
  - Shows effect count in header
  - Each effect card shows: name, enable/disable toggle, remove button
  - Effects are colored based on enabled/disabled state
  - Click to expand/collapse devices section

**Master Section (bottom):**
- Transport controls (Play/Pause/Stop) with timeline
- Master volume control
- Master effects placeholder (to be implemented)

**Benefits:**
- True DAW experience like Ableton Live
- Each track is self-contained with its own effect chain
- No context switching between tabs
- Effects are always visible for each track
- More screen space for waveforms
- Professional mixer-style layout

Note: Effects are visible but not yet applied to audio - that's next!

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

components/tracks/TrackList.tsx

@@ -107,6 +107,22 @@ export function TrackList({
             onLoadAudio={(buffer) =>
               onUpdateTrack(track.id, { audioBuffer: buffer })
             }
+            onToggleEffect={(effectId) => {
+              const updatedChain = {
+                ...track.effectChain,
+                effects: track.effectChain.effects.map((e) =>
+                  e.id === effectId ? { ...e, enabled: !e.enabled } : e
+                ),
+              };
+              onUpdateTrack(track.id, { effectChain: updatedChain });
+            }}
+            onRemoveEffect={(effectId) => {
+              const updatedChain = {
+                ...track.effectChain,
+                effects: track.effectChain.effects.filter((e) => e.id !== effectId),
+              };
+              onUpdateTrack(track.id, { effectChain: updatedChain });
+            }}
           />
         ))}
       </div>