fix(inventory): ensure stored locations always initialized properly

Fixes Bug #3: Locations disappearing when switching tabs or on reload.

Root cause: inventory.stored could become corrupted (null, array, or
undefined) due to incomplete validation during load/save operations.

Solution - Defense in Depth:

1. **Persistence Layer** (src/core/persistence.js):
   - New validateInventoryStructure() function
   - Validates on loadSettings() and loadChatData()
   - Checks all v2 fields (onPerson, stored, assets, version)
   - Ensures stored is always a plain object
   - Validates stored keys/values using validateStoredInventory()
   - Auto-repairs corrupted data with console warnings
   - Persists repairs immediately

2. **Form State Management** (src/systems/interaction/inventoryActions.js):
   - Enhanced restoreFormStates() to detect deleted locations
   - Cleans up orphaned form states automatically
   - Prevents errors from forms referencing non-existent locations

Validation checks:
- ✓ inventory.stored is object (not null/array/undefined)
- ✓ All stored keys are safe (no __proto__, constructor, etc.)
- ✓ All stored values are strings
- ✓ onPerson and assets are strings
- ✓ version field exists

Auto-repair scenarios:
- Corrupted stored → reset to {}
- Invalid onPerson/assets → reset to "None"
- Missing version → set to 2
- Dangerous keys → removed with warning

Result:
- Locations persist across tab switches ✓
- Empty locations persist ✓
- Data corruption auto-repaired on load ✓
- Orphaned form states cleaned up ✓
- No crashes from invalid data ✓

Fixes: Location disappears when switching tabs or reloading

src/core/persistence.js

@@ -15,6 +15,7 @@ import {
     FEATURE_FLAGS
 } from './state.js';
 import { migrateInventory } from '../utils/migration.js';
+import { validateStoredInventory } from '../utils/security.js';
 
 const extensionName = 'third-party/rpg-companion-sillytavern';
 
@@ -39,6 +40,9 @@ export function loadSettings() {
             saveSettings(); // Persist migrated inventory
         }
     }
+
+    // Validate inventory structure (Bug #3 fix)
+    validateInventoryStructure(extensionSettings.userStats.inventory, 'settings');
 }
 
 /**
@@ -166,5 +170,78 @@ export function loadChatData() {
         }
     }
 
+    // Validate inventory structure (Bug #3 fix)
+    validateInventoryStructure(extensionSettings.userStats.inventory, 'chat');
+
     // console.log('[RPG Companion] Loaded chat data:', savedData);
 }
+
+/**
+ * Validates and repairs inventory structure to prevent corruption.
+ * Ensures all v2 fields exist and are the correct type.
+ * Fixes Bug #3: Location disappears when switching tabs
+ *
+ * @param {Object} inventory - Inventory object to validate
+ * @param {string} source - Source of load ('settings' or 'chat') for logging
+ * @private
+ */
+function validateInventoryStructure(inventory, source) {
+    if (!inventory || typeof inventory !== 'object') {
+        console.error(`[RPG Companion] Invalid inventory from ${source}, resetting to defaults`);
+        extensionSettings.userStats.inventory = {
+            version: 2,
+            onPerson: "None",
+            stored: {},
+            assets: "None"
+        };
+        saveSettings();
+        return;
+    }
+
+    let needsSave = false;
+
+    // Ensure v2 structure
+    if (inventory.version !== 2) {
+        console.warn(`[RPG Companion] Inventory from ${source} missing version, setting to 2`);
+        inventory.version = 2;
+        needsSave = true;
+    }
+
+    // Validate onPerson field
+    if (typeof inventory.onPerson !== 'string') {
+        console.warn(`[RPG Companion] Invalid onPerson from ${source}, resetting to "None"`);
+        inventory.onPerson = "None";
+        needsSave = true;
+    }
+
+    // Validate stored field (CRITICAL for Bug #3)
+    if (!inventory.stored || typeof inventory.stored !== 'object' || Array.isArray(inventory.stored)) {
+        console.error(`[RPG Companion] Corrupted stored inventory from ${source}, resetting to empty object`);
+        inventory.stored = {};
+        needsSave = true;
+    } else {
+        // Validate stored object keys/values
+        const cleanedStored = validateStoredInventory(inventory.stored);
+        if (JSON.stringify(cleanedStored) !== JSON.stringify(inventory.stored)) {
+            console.warn(`[RPG Companion] Cleaned dangerous/invalid stored locations from ${source}`);
+            inventory.stored = cleanedStored;
+            needsSave = true;
+        }
+    }
+
+    // Validate assets field
+    if (typeof inventory.assets !== 'string') {
+        console.warn(`[RPG Companion] Invalid assets from ${source}, resetting to "None"`);
+        inventory.assets = "None";
+        needsSave = true;
+    }
+
+    // Persist repairs if needed
+    if (needsSave) {
+        console.log(`[RPG Companion] Repaired inventory structure from ${source}, saving...`);
+        saveSettings();
+        if (source === 'chat') {
+            saveChatData();
+        }
+    }
+}

src/systems/interaction/inventoryActions.js

@@ -539,6 +539,7 @@ export function getInventoryRenderOptions() {
 /**
  * Restores the state of inline forms after re-rendering.
  * This ensures forms that were open before re-render are shown again.
+ * Also cleans up orphaned form states for deleted locations (Bug #3 fix).
  */
 export function restoreFormStates() {
     // Restore add location form
@@ -570,15 +571,31 @@ export function restoreFormStates() {
     }
 
     // Restore add item stored forms (for each location)
+    // Clean up orphaned states for deleted locations (Bug #3 fix)
     if (openForms.addItemStored && typeof openForms.addItemStored === 'object') {
+        const inventory = extensionSettings.userStats.inventory;
+        const locationsToDelete = [];
+
         for (const location in openForms.addItemStored) {
             if (openForms.addItemStored[location]) {
+                // Check if location still exists in inventory
+                if (inventory?.stored && inventory.stored.hasOwnProperty(location)) {
+                    // Location exists, restore form
                     const locationId = location.replace(/\s+/g, '-');
                     const form = $(`#rpg-add-item-form-stored-${locationId}`);
                     if (form.length > 0) {
                         form.show();
                     }
+                } else {
+                    // Location was deleted, mark for cleanup
+                    locationsToDelete.push(location);
                 }
             }
         }
+
+        // Clean up orphaned form states
+        for (const location of locationsToDelete) {
+            delete openForms.addItemStored[location];
+        }
+    }
 }