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/core/persistence.js

@@ -23,7 +23,7 @@ import { validateStoredInventory, cleanItemString } from '../utils/security.js';
 import { migrateToV3JSON } from '../utils/jsonMigration.js';
 
 const extensionName = 'third-party/rpg-companion-sillytavern';
-const CURRENT_SETTINGS_VERSION = 5;
+const CURRENT_SETTINGS_VERSION = 7;
 
 const DEFAULT_USER_STATS = {
     health: 100,
@@ -616,6 +616,69 @@ export function loadSettings() {
                 settingsChanged = true;
             }
 
+            // Migration to version 6: Add equipment data structure
+            if (currentVersion < 6) {
+                // console.log('[RPG Companion] Migrating settings to version 6 (adding equipment)');
+                if (!extensionSettings.userStats.equipment) {
+                    extensionSettings.userStats.equipment = {
+                        items: [],
+                        slots: {
+                            helmet: null,
+                            ring1: null,
+                            ring2: null,
+                            ring3: null,
+                            ring4: null,
+                            ring5: null,
+                            ring6: null,
+                            ring7: null,
+                            ring8: null,
+                            ring9: null,
+                            ring10: null,
+                            necklace: null,
+                            bodyArmor: null,
+                            pants: null,
+                            shoes: null,
+                            gloves: null,
+                            accessory1: null,
+                            accessory2: null,
+                            accessory3: null
+                        }
+                    };
+                }
+                if (extensionSettings.showEquipment === undefined) {
+                    extensionSettings.showEquipment = true;
+                }
+                extensionSettings.settingsVersion = 6;
+                settingsChanged = true;
+            }
+
+            // Migration to version 7: Convert equipment types to generic categories + add item.slot
+            if (currentVersion < 7) {
+                const equipment = extensionSettings.userStats?.equipment;
+                if (equipment) {
+                    const typeMap = {
+                        ring1: 'ring', ring2: 'ring', ring3: 'ring', ring4: 'ring', ring5: 'ring',
+                        ring6: 'ring', ring7: 'ring', ring8: 'ring', ring9: 'ring', ring10: 'ring',
+                        accessory1: 'accessory', accessory2: 'accessory', accessory3: 'accessory'
+                    };
+                    for (const item of equipment.items || []) {
+                        if (!item.slot && equipment.slots) {
+                            for (const [slotId, itemId] of Object.entries(equipment.slots)) {
+                                if (itemId === item.id) {
+                                    item.slot = slotId;
+                                    break;
+                                }
+                            }
+                        }
+                        if (item.type && typeMap[item.type]) {
+                            item.type = typeMap[item.type];
+                        }
+                    }
+                }
+                extensionSettings.settingsVersion = 7;
+                settingsChanged = true;
+            }
+
             // Normalize additive settings without introducing another schema bump.
             if (!extensionSettings.thoughtsInChatStyle) {
                 extensionSettings.thoughtsInChatStyle = 'corner';