feat: add Equipment tab with slot-type validation

Add a new Equipment tab to manage player gear and stat bonuses.

Features:
- 19 equipment slots across 8 categories (helmet, necklace, body armor, gloves, pants, shoes, rings, accessories)
- Type-to-slot validation: each type has max equipped limits (1 helmet, 10 rings, 3 accessories, etc.)
- Auto-slot assignment: equipping a ring fills the first available ring slot
- Stat bonuses from equipped items display on RPG attributes (e.g. STR 10 +2)
- Create/edit modal with stat checkboxes per RPG attribute
- Inventory list for unequipped items

Architecture:
- Shared constants in src/systems/equipment/constants.js
- Category-based types (Ring, Accessory) with auto-slot assignment
- v7 migration converts legacy slot-specific types to generic categories
- Full i18n support for all UI strings

Files:
- New: src/systems/equipment/constants.js
- New: src/systems/interaction/equipmentActions.js
- New: src/systems/rendering/equipment.js
- Modified: state.js, persistence.js, template.html, index.js
- Modified: userStats.js, desktop.js, mobile.js, layout.js, modals.js
- Modified: apiClient.js, sillytavern.js, style.css, en.json

src/systems/ui/modals.js

@@ -22,6 +22,7 @@ import { renderInfoBox } from '../rendering/infoBox.js';
 import { renderThoughts, updateChatThoughts } from '../rendering/thoughts.js';
 import { renderQuests } from '../rendering/quests.js';
 import { renderInventory } from '../rendering/inventory.js';
+import { renderEquipment } from '../rendering/equipment.js';
 import {
     rollDice as rollDiceCore,
     clearDiceRoll as clearDiceRollCore,
@@ -503,6 +504,7 @@ export function setupSettingsPopup() {
         updateDiceDisplayCore();
         updateChatThoughts();
         renderInventory();
+        renderEquipment();
         renderQuests();
 
         // console.log('[RPG Companion] Cache cleared successfully');