Add clarification note in workspace tool instructions

Added clarification in tool instructions about squashing commits.
Noted the importance of squashing commits from newest to oldest as per project status order.
This change helps maintain commit history consistency when using the squash tool.

Author: estib-vega

crates/but-tools/src/workspace.rs

@@ -1177,6 +1177,8 @@ impl Tool for SquashCommits {
         <important_notes>
             This tool allows you to squash a sequence of commits in a stack into a single commit with a new message.
             Use this tool to clean up commit history before merging or sharing.
+            Always squash the commits down, meanding newer commits into their parents.
+            Remember that the commits listed in the project status are in reverse order, so the first commit in the list is the newest one.
         </important_notes>
         ".to_string()
     }