feat: Update .gitignore for clarity and add security plan for sample web app

Author: emmanuelknafo

.gitignore

@@ -3,7 +3,8 @@
 ##
 ## Get latest from https://github.com/github/gitignore/blob/main/VisualStudio.gitignore
 
-# HVE-Core
+# HVE-Core temporary files
+# Copilot tracking
 .copilot-tracking/
 
 # User-specific files