Automatically keep edits if they are included in a commit (#32093)

Release Notes:

- Improved the review experience in the agent panel. Now, when you
commit changes (generated by the AI agent) using Git, Zed will
automatically dismiss the agent’s review UI for those changes. This
means you won’t have to manually “keep” or approve changes twice—just
commit, and you’re done.

crates/fs/src/fs.rs

@@ -1456,7 +1456,12 @@ impl FakeFs {
         .unwrap();
     }
 
-    pub fn set_head_for_repo(&self, dot_git: &Path, head_state: &[(RepoPath, String)]) {
+    pub fn set_head_for_repo(
+        &self,
+        dot_git: &Path,
+        head_state: &[(RepoPath, String)],
+        sha: impl Into<String>,
+    ) {
         self.with_git_state(dot_git, true, |state| {
             state.head_contents.clear();
             state.head_contents.extend(
@@ -1464,6 +1469,7 @@ impl FakeFs {
                     .iter()
                     .map(|(path, content)| (path.clone(), content.clone())),
             );
+            state.refs.insert("HEAD".into(), sha.into());
         })
         .unwrap();
     }