Fix migrations and deploy issues + errors + linting

- scan both pending/ and applied/ dirs so remote catch-up works
- fix remote 500s: run.php handles per-statement errors so VIEW rebuilds run after duplicate columns; replace mb_strimwidth with substr (no mbstring extension on server)
- add missing migration: 015_license_custom.sql (column existed in schema.sql but was never migrated)
- remote: fgetcsv enclosure single-char + AdminLogger permission-denied
guard + deploy always migrates
- fix admin-filters wrapping: restore flex-wrap, flex-basis on
inputs/selects, shrink-protect buttons
- fix phpstan: remove redundant ?? [] after isset guard in
ThesisEditController
- biome: exclude vendored min.js via includes patterns;
lint whole js dir; modernise beforeunload-guard.js

app/src/Controllers/ExportController.php

@@ -122,7 +122,7 @@ class ExportController
      */
     public function createExportZip(?string $baseDir = null): string
     {
-        $baseDir = $baseDir ?? 'files';
+        $baseDir ??= 'files';
         $storageRoot = defined('STORAGE_ROOT') ? STORAGE_ROOT : APP_ROOT . '/storage';
         $files = $this->getAllThesisFiles();
         $manifest = $this->buildExportManifest();