fix(tests): add delay after send_keys in waiter test

why: test_wait_for_any_content_exact_match was flaky on CI due to race
condition where pane content was captured before terminal finished
redrawing after clear command.
what:
- Add time.sleep(0.3) after send_keys("clear") to let terminal redraw
- Fixes timeout failures on tmux 3.3a and 3.4 in CI

Author: tony

tests/_internal/test_waiter.py

@@ -1415,6 +1415,7 @@ def test_wait_for_any_content_exact_match(wait_pane: Pane) -> None:
     """
     # Clear the pane and add specific content
     wait_pane.send_keys("clear", enter=True)
+    time.sleep(0.3)  # Let terminal redraw after clear
 
     # Capture the current content to match it exactly later
     content = wait_pane.capture_pane()