Fix library path saving - auto-create directory and improve error handling

src/routes/settings.js

@@ -44,12 +44,19 @@ router.patch('/', async (req, res) => {
     const { libraryPath } = req.body;
     
     if (libraryPath) {
-      // Validate path exists
+      // Resolve path (handle relative paths)
+      const resolvedPath = path.isAbsolute(libraryPath) 
+        ? libraryPath 
+        : path.join(process.cwd(), libraryPath);
+      
+      // Try to create directory if it doesn't exist
       try {
-        await fs.access(libraryPath);
+        await fs.mkdir(resolvedPath, { recursive: true });
         config.libraryPath = libraryPath;
       } catch (error) {
-        return res.status(400).json({ error: 'Library path does not exist' });
+        return res.status(400).json({ 
+          error: `Cannot create or access path: ${error.message}` 
+        });
       }
     }