Add find-replace-file tool, use it by default over edit-files-tool (#27438)

@agu-z and paired on trying out a "one tool call per edit" approach for
editing files. (The previous approach is still available, it's just
unchecked by default for now.)

Release Notes:

- N/A

---------

Co-authored-by: Agus <agus@zed.dev>

crates/assistant_tools/src/assistant_tools.rs

@@ -5,12 +5,14 @@ mod delete_path_tool;
 mod diagnostics_tool;
 mod edit_files_tool;
 mod fetch_tool;
+mod find_replace_file_tool;
 mod list_directory_tool;
 mod move_path_tool;
 mod now_tool;
 mod path_search_tool;
 mod read_file_tool;
 mod regex_search_tool;
+mod replace;
 mod thinking_tool;
 
 use std::sync::Arc;
@@ -27,6 +29,7 @@ use crate::delete_path_tool::DeletePathTool;
 use crate::diagnostics_tool::DiagnosticsTool;
 use crate::edit_files_tool::EditFilesTool;
 use crate::fetch_tool::FetchTool;
+use crate::find_replace_file_tool::FindReplaceFileTool;
 use crate::list_directory_tool::ListDirectoryTool;
 use crate::now_tool::NowTool;
 use crate::path_search_tool::PathSearchTool;
@@ -43,6 +46,7 @@ pub fn init(http_client: Arc<HttpClientWithUrl>, cx: &mut App) {
     registry.register_tool(CreateFileTool);
     registry.register_tool(CopyPathTool);
     registry.register_tool(DeletePathTool);
+    registry.register_tool(FindReplaceFileTool);
     registry.register_tool(MovePathTool);
     registry.register_tool(DiagnosticsTool);
     registry.register_tool(EditFilesTool);