Fix LogDrawer slowdown from unbounded line accumulation

[Copilot]

LogDrawer never trimmed old lines from its RichTextCtrl, so each append got progressively slower as the log grew without bound.

Changes

• log_drawer.py — Add _MAX_LINE_COUNT = 5000. After each batch of text is written to the textarea, trim leading lines when the count exceeds the limit using wxPython's efficient positional deletion:

  line_count = textarea.GetNumberOfLines()
  if line_count > _MAX_LINE_COUNT:
      lines_to_remove = line_count - _MAX_LINE_COUNT
      end_of_removed = textarea.XYToPosition(0, lines_to_remove)
      textarea.Remove(0, end_of_removed)

• test_log_drawer.py — Add skipped stub test_when_write_many_lines_to_writer_beyond_max_then_leading_lines_trimmed, consistent with existing stubs in the file.
• RELEASE_NOTES.md — Document under a new "Performance improvements" section.

Original prompt

Fix the depicted issue where LogDrawer appends new lines slower and slower over time, because old lines are never cleared out.

Probably want to define a (generous) max line count, perhaps 5,000 lines, and configure the text area to remove leading lines when count exceeds that amount. Hopefully wxPython provides APIs that allow line ranges in a text area to be deleted efficiently.

The user has attached the following file paths as relevant context:

• .github/copilot-instructions.md

Created from VS Code.

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