feat: make breadcrumbs sticky on file list view

frontend/src/css/base.css

@@ -96,6 +96,9 @@ main {
   height: 3em;
   background: var(--background);
   border-bottom: 1px solid var(--divider);
+  position: sticky;
+  z-index: 1000;
+  top: 4em;
 }
 
 .breadcrumbs span,

frontend/src/css/styles.css

@@ -351,6 +351,8 @@ main .spinner .bounce2 {
 #editor-container .breadcrumbs {
   height: 2.3em;
   padding: 0 1em;
+  position: relative;
+  top: 0;
 }
 
 /*** RTL - flip and position arrow of path ***/