Fix a bunch of other low-hanging style lints (#36498)

- **Fix a bunch of low hanging style lints like unnecessary-return**
- **Fix single worktree violation**
- **And the rest**

Release Notes:

- N/A

crates/agent2/src/tools/read_file_tool.rs

@@ -175,7 +175,7 @@ impl AgentTool for ReadFileTool {
                 buffer
                     .file()
                     .as_ref()
-                    .map_or(true, |file| !file.disk_state().exists())
+                    .is_none_or(|file| !file.disk_state().exists())
             })? {
                 anyhow::bail!("{file_path} not found");
             }