fix(tui): propagate errors in insert_history_lines_to_writer (#4266)

## What?
Fixed error handling in `insert_history_lines_to_writer` where all
terminal operations were silently ignoring errors via `.ok()`.

  ## Why?
Silent I/O failures could leave the terminal in an inconsistent state
(e.g., scroll region not reset) with no way to debug. This violates Rust
error handling best practices.

  ## How?
  - Changed function signature to return `io::Result<()>`
  - Replaced all `.ok()` calls with `?` operator to propagate errors
- Added `tracing::warn!` in wrapper function for backward compatibility
  - Updated 15 test call sites to handle Result  with `.expect()`

  ## Testing
  - ✅ Pass all tests

  ## Type of Change
  - [x] Bug fix (non-breaking change)

---------

Signed-off-by: Huaiwu Li <lhwzds@gmail.com>
Co-authored-by: Eric Traut <etraut@openai.com>

codex-rs/tui/tests/suite/vt100_history.rs

@@ -36,7 +36,8 @@ impl TestScenario {
     }
 
     fn run_insert(&mut self, lines: Vec<Line<'static>>) {
-        codex_tui::insert_history::insert_history_lines(&mut self.term, lines);
+        codex_tui::insert_history::insert_history_lines(&mut self.term, lines)
+            .expect("Failed to insert history lines in test");
     }
 }
 

codex-rs/tui/tests/suite/vt100_live_commit.rs

@@ -26,7 +26,8 @@ fn live_001_commit_on_overflow() {
     let commit_rows = rb.drain_commit_ready(3);
     let lines: Vec<Line<'static>> = commit_rows.into_iter().map(|r| r.text.into()).collect();
 
-    codex_tui::insert_history::insert_history_lines(&mut term, lines);
+    codex_tui::insert_history::insert_history_lines(&mut term, lines)
+        .expect("Failed to insert history lines in test");
 
     let screen = term.backend().vt100().screen();