feat: ignore directories with leading underscore in scanner and UI

src/app/page.tsx

@@ -53,7 +53,10 @@ async function getInitialMedia() {
       distinct: ['directory'],
       orderBy: { directory: 'asc' }
     });
-    const directories = dirs.map(d => d.directory).filter(Boolean);
+    const directories = dirs
+      .map(d => d.directory)
+      .filter(Boolean)
+      .filter(d => !d.startsWith('_'));
 
     // Serialize BigInt values for client
     return {

src/lib/media/types.ts

@@ -145,6 +145,7 @@ export function isExcludedFile(filename: string): boolean {
  * Check if a directory should be excluded from scanning.
  */
 export function isExcludedDirectory(dirname: string): boolean {
+  if (dirname.startsWith('_')) return true;
   return EXCLUDED_DIRECTORIES.has(dirname.toLowerCase());
 }