sketch/webui: add untracked files notification to diff view

Add warning in diff view about untracked files.

Co-Authored-By: sketch <hello@sketch.dev>
Change-ID: s45fbbdf5b3d703e4k
diff --git a/webui/src/web-components/demo/mock-git-data-service.ts b/webui/src/web-components/demo/mock-git-data-service.ts
index 6b5df65..3316e1f 100644
--- a/webui/src/web-components/demo/mock-git-data-service.ts
+++ b/webui/src/web-components/demo/mock-git-data-service.ts
@@ -561,4 +561,15 @@
     );
     // Return void as per interface
   }
+
+  async getUntrackedFiles(): Promise<string[]> {
+    console.log("[MockGitDataService] Getting untracked files");
+    // Return some mock untracked files for demo purposes
+    return [
+      "temp.txt",
+      "debug.log",
+      "config/local.json",
+      "node_modules/.cache/something"
+    ];
+  }
 }