feat: integrate ImportDialog into file upload flow

Now when users upload an audio file, they see the ImportDialog with options:

**User Flow:**
1. User selects audio file (click or drag-drop)
2. File is pre-decoded to extract metadata (sample rate, channels)
3. ImportDialog shows with file info and import options:
   - Convert to Mono (if stereo/multi-channel)
   - Resample Audio (44.1kHz - 192kHz)
   - Normalize on Import
4. User clicks Import (or Cancel)
5. File is imported with selected transformations applied
6. Track name auto-updates to filename

**Track.tsx Changes:**
- Added import dialog state (showImportDialog, pendingFile, fileMetadata)
- Updated handleFileChange to show dialog instead of direct import
- Added handleImport to process file with user-selected options
- Added handleImportCancel to dismiss dialog
- Renders ImportDialog when showImportDialog is true
- Logs imported audio metadata to console

Now users can see and control all import transformations!

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

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

components/tracks/Track.tsx

@@ -15,6 +15,8 @@ import { createAutomationPoint } from '@/lib/audio/automation/utils';
 import { createAutomationLane } from '@/lib/audio/automation-utils';
 import { EffectDevice } from '@/components/effects/EffectDevice';
 import { EffectBrowser } from '@/components/effects/EffectBrowser';
+import { ImportDialog } from '@/components/dialogs/ImportDialog';
+import { importAudioFile, type ImportOptions } from '@/lib/audio/decoder';
 
 export interface TrackProps {
   track: TrackType;
@@ -86,6 +88,11 @@ export function Track({
   const resizeStartRef = React.useRef({ y: 0, height: 0 });
   const [effectBrowserOpen, setEffectBrowserOpen] = React.useState(false);
 
+  // Import dialog state
+  const [showImportDialog, setShowImportDialog] = React.useState(false);
+  const [pendingFile, setPendingFile] = React.useState<File | null>(null);
+  const [fileMetadata, setFileMetadata] = React.useState<{ sampleRate?: number; channels?: number }>({});
+
   // Selection state
   const [isSelecting, setIsSelecting] = React.useState(false);
   const [selectionStart, setSelectionStart] = React.useState<number | null>(null);
@@ -452,24 +459,55 @@ export function Track({
     if (!file || !onLoadAudio) return;
 
     try {
+      // Decode to get basic metadata before showing dialog
       const arrayBuffer = await file.arrayBuffer();
       const audioContext = new AudioContext();
-      const audioBuffer = await audioContext.decodeAudioData(arrayBuffer);
-      onLoadAudio(audioBuffer);
+      const tempBuffer = await audioContext.decodeAudioData(arrayBuffer);
 
-      // Update track name to filename if it's still default
-      if (track.name === 'New Track' || track.name === 'Untitled Track') {
-        const fileName = file.name.replace(/\.[^/.]+$/, '');
-        onNameChange(fileName);
-      }
+      // Set metadata and show import dialog
+      setFileMetadata({
+        sampleRate: tempBuffer.sampleRate,
+        channels: tempBuffer.numberOfChannels,
+      });
+      setPendingFile(file);
+      setShowImportDialog(true);
     } catch (error) {
-      console.error('Failed to load audio file:', error);
+      console.error('Failed to read audio file metadata:', error);
     }
 
     // Reset input
     e.target.value = '';
   };
 
+  const handleImport = async (options: ImportOptions) => {
+    if (!pendingFile || !onLoadAudio) return;
+
+    try {
+      setShowImportDialog(false);
+      const { buffer, metadata } = await importAudioFile(pendingFile, options);
+      onLoadAudio(buffer);
+
+      // Update track name to filename if it's still default
+      if (track.name === 'New Track' || track.name === 'Untitled Track') {
+        const fileName = metadata.fileName.replace(/\.[^/.]+$/, '');
+        onNameChange(fileName);
+      }
+
+      console.log('Audio imported:', metadata);
+    } catch (error) {
+      console.error('Failed to import audio file:', error);
+    } finally {
+      setPendingFile(null);
+      setFileMetadata({});
+    }
+  };
+
+  const handleImportCancel = () => {
+    setShowImportDialog(false);
+    setPendingFile(null);
+    setFileMetadata({});
+  };
+
   const handleLoadAudioClick = () => {
     fileInputRef.current?.click();
   };
@@ -1005,6 +1043,17 @@ export function Track({
           <div className="absolute inset-x-0 bottom-0 h-px bg-border group-hover:bg-primary transition-colors duration-200" />
         </div>
       )}
+
+      {/* Import Dialog */}
+      {showImportDialog && pendingFile && (
+        <ImportDialog
+          fileName={pendingFile.name}
+          originalSampleRate={fileMetadata.sampleRate}
+          originalChannels={fileMetadata.channels}
+          onImport={handleImport}
+          onCancel={handleImportCancel}
+        />
+      )}
     </div>
   );
 }