feat(inventory): wire up v2 system to main panel with full interactivity

- Add inventory section to template.html between Thoughts and bottom controls
- Wire up renderInventory() to all event handlers (message received, character changed, swipes)
- Initialize inventory container reference and event listeners in index.js
- Add showInventory toggle checkbox to settings with visibility control
- Update layout.js to handle inventory section and divider visibility
- Add renderInventory parameter to updateRPGData for separate mode support
- Update state.js and config.js with inventory container and showInventory setting

Inventory is now fully integrated as a visible, interactive panel section that persists across all user interactions.

src/core/config.js

@@ -29,6 +29,7 @@ export const defaultSettings = {
     showUserStats: true,
     showInfoBox: true,
     showCharacterThoughts: true,
+    showInventory: true, // Show inventory section (v2 system)
     showThoughtsInChat: true, // Show thoughts overlay in chat
     enableHtmlPrompt: false, // Enable immersive HTML prompt injection
     enablePlotButtons: true, // Show plot progression buttons above chat input
@@ -71,5 +72,6 @@ export const defaultSettings = {
         wis: 10,
         cha: 10
     },
-    lastDiceRoll: null // Store last dice roll result
+    lastDiceRoll: null, // Store last dice roll result
+    collapsedInventoryLocations: [] // Array of collapsed storage location names
 };