refactor: remove configurable track height setting

Removed the defaultTrackHeight setting from UI preferences as it doesn't need
to be user-configurable. All tracks now use DEFAULT_TRACK_HEIGHT constant (400px).

Changes:
- Removed defaultTrackHeight from UISettings interface
- Removed track height slider from GlobalSettingsDialog
- Updated AudioEditor to use DEFAULT_TRACK_HEIGHT constant directly
- Simplified dependency arrays in addTrack callbacks

This simplifies the settings interface while maintaining the same visual behavior.

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

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

components/editor/AudioEditor.tsx

@@ -33,6 +33,7 @@ import { formatDuration } from '@/lib/audio/decoder';
 import { useHistory } from '@/lib/hooks/useHistory';
 import { useRecording } from '@/lib/hooks/useRecording';
 import { useSettings } from '@/lib/hooks/useSettings';
+import { DEFAULT_TRACK_HEIGHT } from '@/types/track';
 import type { EffectType } from '@/lib/audio/effects/chain';
 import {
   createMultiTrackCutCommand,
@@ -149,19 +150,19 @@ export function AudioEditor() {
   // Wrap addTrack to auto-select first track when adding to empty project
   const addTrack = React.useCallback((name?: string) => {
     const shouldAutoSelect = shouldAutoSelectRef.current;
-    const track = addTrackOriginal(name, settings.ui.defaultTrackHeight);
+    const track = addTrackOriginal(name, DEFAULT_TRACK_HEIGHT);
     if (shouldAutoSelect) {
       setSelectedTrackId(track.id);
       shouldAutoSelectRef.current = false; // Only auto-select once
     }
     return track;
-  }, [addTrackOriginal, settings.ui.defaultTrackHeight]);
+  }, [addTrackOriginal]);
 
   // Wrap addTrackFromBuffer to auto-select first track when adding to empty project
   const addTrackFromBuffer = React.useCallback((buffer: AudioBuffer, name?: string) => {
     console.log(`[AudioEditor] addTrackFromBuffer wrapper called: ${name}, shouldAutoSelect: ${shouldAutoSelectRef.current}`);
     const shouldAutoSelect = shouldAutoSelectRef.current;
-    const track = addTrackFromBufferOriginal(buffer, name, settings.ui.defaultTrackHeight);
+    const track = addTrackFromBufferOriginal(buffer, name, DEFAULT_TRACK_HEIGHT);
     console.log(`[AudioEditor] Track created: ${track.name} (${track.id})`);
     if (shouldAutoSelect) {
       console.log(`[AudioEditor] Auto-selecting track: ${track.id}`);
@@ -169,7 +170,7 @@ export function AudioEditor() {
       shouldAutoSelectRef.current = false; // Only auto-select once
     }
     return track;
-  }, [addTrackFromBufferOriginal, settings.ui.defaultTrackHeight]);
+  }, [addTrackFromBufferOriginal]);
 
   // Track which parameters are being touched (for touch/latch modes)
   const [touchedParameters, setTouchedParameters] = React.useState<Set<string>>(new Set());

components/settings/GlobalSettingsDialog.tsx

@@ -400,29 +400,6 @@ export function GlobalSettingsDialog({
                     Adjust the UI font size. Requires reload.
                   </p>
                 </div>
-
-                {/* Default Track Height */}
-                <div className="space-y-2">
-                  <div className="flex items-center justify-between">
-                    <label className="text-sm font-medium">Default Track Height</label>
-                    <span className="text-xs font-mono text-muted-foreground">
-                      {settings.ui.defaultTrackHeight}px
-                    </span>
-                  </div>
-                  <Slider
-                    value={[settings.ui.defaultTrackHeight]}
-                    onValueChange={([value]) =>
-                      onUISettingsChange({ defaultTrackHeight: value })
-                    }
-                    min={120}
-                    max={600}
-                    step={20}
-                    className="w-full"
-                  />
-                  <p className="text-xs text-muted-foreground">
-                    Initial height for new tracks. Default: 400px.
-                  </p>
-                </div>
               </div>
             )}
 

lib/hooks/useSettings.ts

@@ -11,7 +11,6 @@ export interface AudioSettings {
 export interface UISettings {
   theme: 'dark' | 'light' | 'auto';
   fontSize: 'small' | 'medium' | 'large';
-  defaultTrackHeight: number; // 120-400px
 }
 
 export interface EditorSettings {
@@ -45,7 +44,6 @@ const DEFAULT_SETTINGS: Settings = {
   ui: {
     theme: 'dark',
     fontSize: 'medium',
-    defaultTrackHeight: 400,
   },
   editor: {
     autoSaveInterval: 3, // 3 seconds