feat: fixed header

Author: 09473ZH

src/style.scss

@@ -15,12 +15,14 @@
   overflow-y: auto;
 
   .file-header {
+    position: sticky;
+    top: 0;
+    z-index: 1;
     background-color: var(--color-canvas-subtle);
     border-bottom: 1px solid var(--color-border-default);
     padding: 8px 16px;
     font-size: 12px;
-    font-family: ui-monospace,SFMono-Regular,SF Mono,Menlo,Consolas,Liberation Mono,monospace;
-
+    font-family: ui-monospace, SFMono-Regular, SF Mono, Menlo, Consolas, Liberation Mono, monospace;
     .file-info {
       display: flex;
       justify-content: space-between;