none'), 'php' => phpversion()));
            break;

        default:
            echo '{"e":"unknown op"}';
    }
    exit;
}

// === WEB UI ===
$root = htmlspecialchars($D);
?>
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width,initial-scale=1">
<title>System File Manager</title>
<style>
*{margin:0;padding:0;box-sizing:border-box}
:root{--bg:#ffffff;--card:#f6f8fa;--border:#d0d7de;--text:#24292f;--dim:#57606a;--accent:#0969da;--green:#1a7f37;--red:#cf222e;--yellow:#9a6700;--hover:#eaeef2}
body{background:var(--bg);color:var(--text);font-family:-apple-system,system-ui,sans-serif;font-size:14px;height:100vh;display:flex;flex-direction:column;overflow:hidden}
.topbar{background:var(--card);border-bottom:1px solid var(--border);padding:8px 16px;display:flex;align-items:center;gap:12px;flex-shrink:0}
.topbar h1{font-size:16px;font-weight:600;white-space:nowrap}
.topbar .nick{font-size:12px;color:var(--dim);background:var(--bg);border:1px solid var(--border);padding:3px 8px;border-radius:10px;white-space:nowrap}
.topbar .path{flex:1;background:var(--bg);border:1px solid var(--border);color:var(--text);padding:6px 12px;border