Chestifier

Fixes and hardening

• Fixed a crash when the highlight color in the config was invalid (hand-edited or corrupted): it now falls back to the default instead of crashing the render every frame.
• Fixed a crash risk when sorting/matching against a chest with zero slots.
• Fixed a latent bug in the enchantment sort comparison that could throw under certain inventory states.
• Corrupt/unreadable config files are now backed up to chestifier.json.bak before falling back to defaults, so a bad config no longer silently destroys your settings.
• The search box no longer leaks its text/focus state between different opened chests.
• Errors from optional third-party mod integrations are now logged properly instead of being silently swallowed.
• Fixed the frozen-slot marker rendering on top of items instead of behind them.
• Various internal cleanup: shared layout constants, deduplicated code, clearer naming.