fix: use DEFAULT_TRACK_HEIGHT constant for consistent track heights

- Import DEFAULT_TRACK_HEIGHT and COLLAPSED_TRACK_HEIGHT from types
- Use DEFAULT_TRACK_HEIGHT (340px) instead of hardcoded 240px fallback
- Ensures all tracks have the same height as the first track
- Matches the height used when creating tracks

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

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

components/tracks/TrackList.tsx

@@ -7,6 +7,7 @@ import { Track } from './Track';
 import { TrackExtensions } from './TrackExtensions';
 import { ImportTrackDialog } from './ImportTrackDialog';
 import type { Track as TrackType } from '@/types/track';
+import { DEFAULT_TRACK_HEIGHT, COLLAPSED_TRACK_HEIGHT } from '@/types/track';
 import { createEffect, type EffectType, EFFECT_NAMES } from '@/lib/audio/effects/chain';
 import { AutomationLane } from '@/components/automation/AutomationLane';
 import type { AutomationPoint as AutomationPointType } from '@/types/automation';
@@ -210,7 +211,7 @@ export function TrackList({
                 <div
                   className="flex flex-col"
                   style={{
-                    height: track.collapsed ? '48px' : `${track.height || 240}px`
+                    height: track.collapsed ? `${COLLAPSED_TRACK_HEIGHT}px` : `${track.height || DEFAULT_TRACK_HEIGHT}px`
                   }}
                 >
                   {/* Waveform - Takes remaining space */}