fix: serve theme assets from the production host, keep images on the CDN

deploy.php

@@ -52,7 +52,10 @@ $rsyncOptions = [
     'filter' => [],
     'filter-file' => false,
     'filter-perdir' => false,
-    'flags' => 'rz',
+    // -t preserves mtimes: without it every file lands with a fresh timestamp, so unchanged
+    // files get a new Last-Modified on every deploy and every conditional request revalidates
+    // into a full response instead of a 304.
+    'flags' => 'rzt',
     'options' => ['delete', 'links', 'chmod=D755,F664'],
     'timeout' => 300,
 ];