crash.log written into repo root on Linux (breaks Syncthing casing sync)

Empieza en plotruler/main.py, en _crash_log_path(), e inspecciona cómo se comporta el fallback cuando LOCALAPPDATA y TEMP no están definidos en Linux. Elige e implementa una ubicación adecuada para la plataforma que no pueda crear un directorio PlotRuler con mayúscula inicial en el repositorio; después, verifica que crash.log se escriba fuera del árbol de trabajo; considera la sugerencia relacionada de .gitignore.

Summary

When run on Linux with LOCALAPPDATA/TEMP unset, _crash_log_path() falls back to ".", so the crash log is written to ./PlotRuler/crash.log inside the repository working tree.

Code

plotruler/__main__.py:

def _crash_log_path():
    base = os.environ.get("LOCALAPPDATA") or os.environ.get("TEMP") or "."
    return os.path.join(base, "PlotRuler", "crash.log")

• Windows: LOCALAPPDATA is set → %LOCALAPPDATA%\PlotRuler\crash.log (fine).
• Linux/macOS: neither var is set → logs to ./PlotRuler/crash.log.

Problem

The repo root already contains the lowercase package plotruler/. On case-insensitive filesystems (Windows/macOS) the two collide, and tools that sync the tree — e.g. Syncthing — report a casing conflict:

remote "Programming\GraphRuler\PlotRuler" uses different upper or lowercase characters than local "Programming\GraphRuler\plotruler"

so the items never sync until the stray PlotRuler/ dir is deleted manually.

Suggestion

Use a platform-appropriate XDG path on non-Windows, e.g.:

base = os.environ.get("LOCALAPPDATA") or os.environ.get("XDG_STATE_HOME", os.path.expanduser("~/.local/state"))

and/or log with the app name directly rather than a capital-cased dir that can shadow the lowercase package. Also consider ignoring the runtime dir in .gitignore as a belt-and-suspenders measure.