fix: expand every folder by default in the explorer tree

The file tree opened collapsed, requiring the reviewer to click each
folder before they could see what was inside. Walk the tree on first
render and mark every folder open in $scope.opens. Folders the user
has explicitly toggled (a previous entry already exists in
$scope.opens) are left as-is, so collapsing still works.

Fixes #496.

public/script/app.js

@@ -509,6 +509,22 @@ angular
               });
             }
 
+            // #496 — expand every folder on first load so reviewers see the
+            // whole tree without clicking through. Folders the user has
+            // already toggled (state recorded in $scope.opens) are left
+            // alone, so collapsing a folder still works.
+            function expandAllFolders(nodes, parentPath) {
+              if (!nodes) return;
+              for (const f of nodes) {
+                if (!f.child) continue;
+                const path = `${parentPath}/${f.name}`;
+                if (!(path in $scope.opens)) {
+                  $scope.opens[path] = true;
+                }
+                expandAllFolders(f.child, path);
+              }
+            }
+
             $scope.$watch(
               "file",
               (newValue) => {
@@ -516,6 +532,7 @@ angular
                 if (newValue.length == 0) {
                   return $element.html("Empty repository");
                 }
+                expandAllFolders(toArray(newValue), "");
                 display();
               },
               true