Persistent storage volume + remove debug route + validate logo file exists

- Coolify persistent volume mounted at /app/storage/app (covers public uploads,
  private files, backups). Configured via API:
  POST /api/v1/applications/{uuid}/storages with type=persistent
- getLogoUrl() / getFaviconUrl() now validate file_exists($m->getPath()) before
  returning URL — guards against stale DB rows from pre-volume era
- Removed /debug-storage diagnostic route (used to find the symlink+volume bug)

app/Models/Central/Company.php

@@ -98,12 +98,18 @@ class Company extends BaseTenant implements HasMedia
     public function getLogoUrl(): ?string
     {
         $m = $this->getFirstMedia('logo');
-        return $m ? $m->getUrl() : null;
+        if (! $m) return null;
+        // Validate file actually exists on disk (storage may be ephemeral
+        // and DB row may point to lost file from previous deploy).
+        if (! @file_exists($m->getPath())) return null;
+        return $m->getUrl();
     }
 
     public function getFaviconUrl(): ?string
     {
         $m = $this->getFirstMedia('favicon');
-        return $m ? $m->getUrl() : null;
+        if (! $m) return null;
+        if (! @file_exists($m->getPath())) return null;
+        return $m->getUrl();
     }
 }