fix: detect macOS ACL support using uname instead of chmod output (#4137)

Running `chmod` without arguments to detect macOS ACL support outputs
an error: "chmod: missing operand" which clutters deployment logs.

Since `chmod +a` is macOS-specific (Linux and FreeBSD use setfacl),
directly checking `uname -s === 'Darwin'` is cleaner and more reliable
than parsing chmod's error output.

Author: alies-dev

recipe/deploy/writable.php

@@ -99,8 +99,8 @@
             $remoteUser = run('whoami');
         }
         $httpUser = get('http_user');
-        if (strpos(run("chmod 2>&1; true"), '+a') !== false) {
-            // Try OS-X specific setting of access-rights
+        if (run("uname -s") === 'Darwin') {
+            // macOS supports chmod +a for ACL management
 
             run("$sudo chmod +a \"$httpUser allow delete,write,append,file_inherit,directory_inherit\" $dirs");
             run("$sudo chmod +a \"$remoteUser allow delete,write,append,file_inherit,directory_inherit\" $dirs");