feat(settings): add button to open app data folder

src/routes/settings/+page.svelte

@@ -19,6 +19,8 @@
   import { clearDeezerCache } from '$lib/library/deezer-database';
   import { open, confirm, message } from '@tauri-apps/plugin-dialog';
   import { relaunch } from '@tauri-apps/plugin-process';
+  import { appDataDir } from '@tauri-apps/api/path';
+  import { openPath } from '@tauri-apps/plugin-opener';
 
   let currentMusicFolder = $state<string | null>(null);
   let currentPlaylistsFolder = $state<string | null>(null);
@@ -122,6 +124,21 @@
       }
     }
   }
+
+  async function openAppDataFolder() {
+    try {
+      const dataPath = await appDataDir();
+      console.log('App data path:', dataPath);
+      if (!dataPath) {
+        throw new Error('Could not get app data directory path');
+      }
+      await openPath(dataPath);
+    } catch (error) {
+      console.error('Error opening app data folder:', error);
+      const errorMessage = error instanceof Error ? error.message : String(error);
+      await message('Error opening app data folder: ' + errorMessage, { title: 'Error', kind: 'error' });
+    }
+  }
 </script>
 
 <div style="padding: 8px;">
@@ -339,6 +356,12 @@
             <small class="help-text">This will delete all cached Deezer favorites data. The next time you visit the Deezer page, it will refetch from the API.</small>
             <button onclick={clearDeezerDatabase}>Clear Deezer Cache</button>
           </div>
+
+          <div class="field-row-stacked">
+            <div class="setting-heading">Open App Data Folder</div>
+            <small class="help-text">Opens the application data folder containing SQLite databases and other app data.</small>
+            <button onclick={openAppDataFolder}>Open Folder</button>
+          </div>
         </section>
       {/if}
     </div>