Move Custom Scripts out of the repo and add an Import Script picker

Custom Scripts (the Scheduler page's inline editor) used to save into the
git-tracked Custom/ folder, so anything saved there would end up on GitHub.
They now live in /boot/config/plugins/user.scripts/Varaverk/Scripts, same
folder family as Unraid's own User Scripts plugin. Import Script lets you
browse the whole server and move an existing script in instead of only
creating new ones inline — always a move, never a copy, so no stray
duplicate is left where it came from.

Plugin/unraid/api/script.php

@@ -8,7 +8,7 @@ if ($_SERVER['REQUEST_METHOD'] === 'GET') {
         echo json_encode(['ok' => false, 'error' => 'Invalid id']);
         exit;
     }
-    $path = SCRIPTS_DIR . '/' . $id;
+    $path = CUSTOM_SCRIPTS_DIR . '/' . substr($id, strlen('Custom/'));
     echo json_encode(['ok' => true, 'content' => file_exists($path) ? file_get_contents($path) : '']);
     exit;
 }
@@ -24,7 +24,7 @@ if ($_SERVER['REQUEST_METHOD'] === 'POST') {
     }
 
     $id   = 'Custom/' . $name . '.sh';
-    $path = SCRIPTS_DIR . '/Custom/' . $name . '.sh';
+    $path = CUSTOM_SCRIPTS_DIR . '/' . $name . '.sh';
 
     if ($action === 'delete') {
         if (!file_exists($path)) {
@@ -40,7 +40,7 @@ if ($_SERVER['REQUEST_METHOD'] === 'POST') {
         exit;
     }
 
-    $dir = SCRIPTS_DIR . '/Custom';
+    $dir = CUSTOM_SCRIPTS_DIR;
     if (!is_dir($dir)) mkdir($dir, 0755, true);
     if (file_put_contents($path, $content) === false) {
         echo json_encode(['ok' => false, 'error' => 'Failed to write script']);