Load settings from XDG config file at startup

[hrsather]

Summary

• Adds support for configuring Scroll Reverser via a dotfile at $XDG_CONFIG_HOME/scrollreverser/config (defaults to ~/.config/scrollreverser/config)
• Settings are loaded at app startup and written into NSUserDefaults, so both the UI and the event tap pick them up correctly
• Only keys present in the file are applied; absent keys leave existing preferences untouched

Config file format

# Scroll Reverser
enabled=true
reverseVertical=true
reverseHorizontal=false
reverseTrackpad=false
reverseMouse=true

Supports true/false and 1/0 values, blank lines, and # comments.

Test plan

• Create ~/.config/scrollreverser/config with specific values
• Launch app and verify prefs UI reflects the file contents
• Change a value in the file, restart, confirm it updates
• Verify app behaves normally when no config file is present
• Verify XDG_CONFIG_HOME env var is respected when set

🤖 Generated with Claude Code