agent: Make read_file and edit_file tool call titles more specific (#37639)

For read_file and edit_file, show the worktree-relative path if there's
only one visible worktree, and the "full path" otherwise. Also restores
the display of line numbers for read_file calls.

Release Notes:

- N/A

crates/agent2/src/tools/find_path_tool.rs

@@ -93,7 +93,11 @@ impl AgentTool for FindPathTool {
         acp::ToolKind::Search
     }
 
-    fn initial_title(&self, input: Result<Self::Input, serde_json::Value>) -> SharedString {
+    fn initial_title(
+        &self,
+        input: Result<Self::Input, serde_json::Value>,
+        _cx: &mut App,
+    ) -> SharedString {
         let mut title = "Find paths".to_string();
         if let Ok(input) = input {
             title.push_str(&format!(" matching “`{}`”", input.glob));