fix: copy mobile toggle pattern for refresh button

- Moved refresh button creation from template.html to index.js (appended to body)
- Created new CSS class .rpg-mobile-refresh (exact copy of .rpg-mobile-toggle pattern)
- Uses opacity for show/hide instead of display (CSS controls visibility based on panel state)
- Show when panel open (body:has(.rpg-panel.rpg-mobile-open))
- Hide when panel closed (opacity: 0, pointer-events: none)
- Updated constrainFabToViewport() to accept optional button parameter
- Automatically detects which button and uses correct settings (mobileFabPosition or mobileRefreshPosition)
- Simplified updateGenerationModeUI() - CSS handles visibility
- Kept full drag functionality with touch and mouse support
- Button positioned via JavaScript with saved position
- z-index: 1001 (above panel, below toggle at 10002)

template.html

@@ -54,11 +54,6 @@
                 </div>
             </div>
 
-            <!-- Mobile Floating Refresh Button (shown on all tabs) -->
-            <button id="rpg-manual-update-mobile" class="rpg-refresh-icon-btn" title="Refresh RPG Info">
-                <i class="fa-solid fa-sync"></i>
-            </button>
-
             <!-- HTML Prompt Toggle -->
             <div class="rpg-toggle-container">
                 <label class="rpg-toggle-label">