refactor: move unraid-specific tools into Plugin/unraid/tools/

api_cache_writer, remote_arr_cache_writer, conf_populate, storage_migrate are
all Unraid-adapter-specific — they read Docker appdata paths, Unraid service
configs, and drive the Unraid web plugin cache. They don't belong in Tools/.

- Tools/{4 scripts + php} → Plugin/unraid/tools/
- Fix source depth: ../ → ../../../ (now 3 levels from repo root)
- Fix conf_populate SCRIPTS_ROOT bug: was never set, would expand to empty
- api/arrs.php, api/storage.php: SCRIPTS_DIR/Tools/ → dirname(__DIR__)/tools/
- schedule.json: key IDs updated to Plugin/unraid/tools/...
- Cron rebuilt — live entries updated immediately

Plugin/unraid/api/storage.php

@@ -56,7 +56,7 @@ if ($action === 'migrate' && $_SERVER['REQUEST_METHOD'] === 'POST') {
         exit;
     }
 
-    $script = SCRIPTS_DIR . '/Tools/storage_migrate.sh';
+    $script = dirname(__DIR__) . '/tools/storage_migrate.sh';
     if (!file_exists($script)) {
         echo json_encode(['ok' => false, 'error' => 'storage_migrate.sh not found']);
         exit;