Add configurable library path with settings API and UI

src/routes/settings.js

@@ -0,0 +1,64 @@
+import express from 'express';
+import fs from 'fs/promises';
+import path from 'path';
+
+const router = express.Router();
+
+const CONFIG_FILE = path.join(process.cwd(), 'config.json');
+
+// Default config
+const DEFAULT_CONFIG = {
+  libraryPath: './audio_library',
+  port: 3000
+};
+
+// Load config
+async function loadConfig() {
+  try {
+    const data = await fs.readFile(CONFIG_FILE, 'utf-8');
+    return { ...DEFAULT_CONFIG, ...JSON.parse(data) };
+  } catch (error) {
+    return DEFAULT_CONFIG;
+  }
+}
+
+// Save config
+async function saveConfig(config) {
+  await fs.writeFile(CONFIG_FILE, JSON.stringify(config, null, 2));
+}
+
+// Get settings
+router.get('/', async (req, res) => {
+  try {
+    const config = await loadConfig();
+    res.json(config);
+  } catch (error) {
+    res.status(500).json({ error: error.message });
+  }
+});
+
+// Update settings
+router.patch('/', async (req, res) => {
+  try {
+    const config = await loadConfig();
+    const { libraryPath } = req.body;
+    
+    if (libraryPath) {
+      // Validate path exists
+      try {
+        await fs.access(libraryPath);
+        config.libraryPath = libraryPath;
+      } catch (error) {
+        return res.status(400).json({ error: 'Library path does not exist' });
+      }
+    }
+    
+    await saveConfig(config);
+    res.json({ success: true, config });
+  } catch (error) {
+    res.status(500).json({ error: error.message });
+  }
+});
+
+export default router;
+export { loadConfig };