fix: add debug toggle as draggable mobile FAB button

PROBLEM:
- Debug logs only accessible via browser console (impractical on mobile)
- User (Salixfire) reporting parsing issues but can't debug on mobile device
- Need mobile-friendly debug mode for troubleshooting data display issues

SOLUTION:
Implemented debug toggle FAB button following exact pattern of existing mobile FABs:

Files Changed:
- src/core/state.js: Added debugFabPosition and debugMode to extensionSettings
- src/core/config.js: Added debugFabPosition to defaultSettings (reference)
- index.js: Created debug toggle button, imported setupDebugButtonDrag
- style.css: Added debug toggle CSS matching mobile FAB pattern (44px, grab cursor, theme colors)
- src/systems/ui/mobile.js: Added setupDebugButtonDrag() with drag-to-reposition
- src/systems/ui/debug.js: Removed button creation, added just-dragged check, updated visibility control

Implementation Details:
- Button created in index.js (not debug.js) following mobile FAB pattern
- CSS matches mobile toggle/refresh buttons (44px, theme colors, grab cursor, user-select: none)
- Drag support with touch/mouse handlers, 200ms/10px threshold
- Position saved to extensionSettings.debugFabPosition
- Just-dragged flag prevents accidental clicks after drag
- Mobile (≤1000px): slide from right with rpg-mobile-open/closing classes
- Desktop (>1000px): slide from bottom with rpg-debug-open class
- Event delegation for reliable click handling
- Default position: bottom 140px, left 20px (below other FABs)

Bug Fix:
- Initial implementation had debugFabPosition only in config.js
- extensionSettings uses state.js as source, not config.js
- Without debugFabPosition in state.js, button had no position and was invisible
- Now properly initialized in both files

The debug button is hidden by default (debugMode: false) and shown when user enables debug mode in RPG Companion settings. This allows Salixfire to view parser logs on mobile and troubleshoot the data display issues.

index.js

@@ -99,7 +99,8 @@ import {
     removeMobileTabs,
     setupMobileKeyboardHandling,
     setupContentEditableScrolling,
-    setupRefreshButtonDrag
+    setupRefreshButtonDrag,
+    setupDebugButtonDrag
 } from './src/systems/ui/mobile.js';
 import {
     setupDesktopTabs,
@@ -221,6 +222,14 @@ async function initUI() {
     `;
     $('body').append(mobileRefreshHtml);
 
+    // Add debug toggle FAB button (same pattern as other mobile FABs)
+    const debugToggleHtml = `
+        <button id="rpg-debug-toggle" class="rpg-debug-toggle" title="Toggle Debug Logs">
+            <i class="fa-solid fa-bug"></i>
+        </button>
+    `;
+    $('body').append(debugToggleHtml);
+
     // Cache UI elements using state setters
     setPanelContainer($('#rpg-companion-panel'));
     setUserStatsContainer($('#rpg-user-stats'));
@@ -464,6 +473,7 @@ async function initUI() {
     setupMobileKeyboardHandling();
     setupContentEditableScrolling();
     setupRefreshButtonDrag();
+    setupDebugButtonDrag();
     initInventoryEventListeners();
 
     // Initialize debug UI if debug mode is enabled