dnd5e-buff-on-trigger V1.0.0

Highlight configured item buttons

* Highlight the item sheet lightning button when an item has a usable Buff on Trigger configuration.
* Add configuration-state detection for item flags without confusing item configuration with active actor buffs.
* Mark configured item buttons with active/inactive CSS classes and a data attribute.
* Style inactive buttons as neutral and configured buttons as yellow with a subtle highlight.
* Refresh open item sheet buttons after saving Buff on Trigger configuration changes.
* Add tests for empty flags, default passive configs, usable triggers, roll modifiers, mechanical buffs, statuses, end conditions, stored targets, reset behavior, and actor activeBuffs isolation.
* Document the highlighted lightning icon behavior in the README.
* Preserve all module mechanics, presets, import/export, diagnostics, stacking, active buff handling, Midi-QOL integration, and runtime behavior.