Magic items now reach players through three surfaces: zone loot drops,
Luigi's "Curios" shelf, and combat effects. Effects are formulaic
(Rarity scalar x Kind), mirroring the bestiary tuning pass, with an
empty magicItemEffectOverlay as the hand-authored refinement path.
- magic_items_gameplay.go: rarity index, magic_item_equipped persistence
(new table, DnDSlot-keyed), codified effect formula, applyMagicItemEffects
combat hook, potion/scroll -> ConsumableDef bridge, !adventure equip-magic
- dropZoneLoot: 15% magic-item substitution roll by tier rarity
- Luigi's Curios category: daily UTC-seeded 8-item rotation
- combat_bridge / combat_session_build: applyMagicItemEffects after passives
- consumableDefByName falls through so loot/shop potions auto-resolve
- renderDnDSheet: new Magic Items section
Equippable items live entirely in the DnDSlot scheme, separate from the
legacy tier-gear. Attunement items equip inert until attuned (3-slot cap).
