PR #17996: fix(cli): clear ghost lines on ALL terminal resize events

• Repository: NousResearch/hermes-agent
• Author: unn-Known1
• State: open | merged: False
• Link: https://github.com/NousResearch/hermes-agent/pull/17996

Description (problem / solution / changelog)

Summary

Fixes #17975 - CLI TUI renders blank lines after terminal resize.

Problem

When the terminal resizes (shrink, grow, or height change), the emulator may reflow previously-rendered full-width rows into multiple narrower/taller rows, leaving ghost duplicates visible. The prompt area drifts downward with ghost empty rows.

Root Cause

The previous fix (_resize_clear_ghosts) only handled horizontal shrinking (columns getting smaller) by calculating a reflow factor. It missed:

• Terminal growing (columns getting larger)
• Height changes
• SIGWINCH-less multiplexer-driven resizes

Solution

Use a simpler, more robust approach: force erase_screen() + cursor_goto(0,0) BEFORE the standard resize handler to completely clear any ghost content from the previous render. This handles ALL resize types.

Changes

• cli.py: Simplified _resize_clear_ghosts() to always call erase_screen(), cursor_goto(0,0), and flush() before the original resize handler, rather than conditionally based on resize direction.
• tests/cli/test_cli_resize_ghosts.py: Added test coverage for the resize fix.

Local Verification

• ✅ All existing CLI tests pass (26/26)
• ✅ New resize tests pass (4/4)
• ✅ Python syntax check passed
• ✅ Ruff lint check passed (no new errors)

Notes

This contribution was developed with AI assistance.

Changed files

• cli.py (modified, +13/-31)
• tests/cli/test_cli_resize_ghosts.py (added, +132/-0)