fix: add missing CSS for mobile refresh FAB button

Mobile refresh button was created in HTML but had no CSS styling,
making it invisible. Desktop refresh button was showing on mobile
with wrong sizing.

Changes:
- Added .rpg-mobile-refresh FAB styles (44px, draggable, etc.)
- Show mobile refresh FAB on mobile viewports
- Hide desktop #rpg-manual-update button on mobile
- Added responsive icon sizing for mobile refresh button

Fixes issue where users only saw the desktop refresh button with
incorrect DPI/sizing on mobile devices.

style.css

@@ -3305,6 +3305,45 @@ body:has(.rpg-panel.rpg-position-left) #sheld {
     transform: rotate(180deg);
 }
 
+/* ============================================
+   MOBILE REFRESH FAB BUTTON (Same pattern as mobile toggle)
+   ============================================ */
+.rpg-mobile-refresh {
+    display: none;
+    align-items: center;
+    justify-content: center;
+    position: fixed;
+    /* Position set by JavaScript based on saved settings */
+    width: 44px;
+    height: 44px;
+    border-radius: 50%;
+    background: var(--SmartThemeBlurTintColor);
+    border: 2px solid var(--SmartThemeBorderColor);
+    color: var(--SmartThemeBodyColor);
+    font-size: 1.125rem;
+    cursor: grab;
+    z-index: 1001; /* Below mobile toggle (10002), above debug (1000) */
+    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
+    transition: opacity 0.3s ease, transform 0.2s ease, top 0.3s ease, left 0.3s ease, right 0.3s ease, bottom 0.3s ease;
+    user-select: none;
+    -webkit-user-select: none;
+    will-change: top, left;
+}
+
+.rpg-mobile-refresh.dragging {
+    transition: none;
+    cursor: grabbing;
+}
+
+.rpg-mobile-refresh:hover {
+    transform: scale(1.1);
+    box-shadow: 0 6px 16px rgba(0, 0, 0, 0.4);
+}
+
+.rpg-mobile-refresh:active {
+    transform: scale(0.95);
+}
+
 /* Mobile overlay backdrop */
 .rpg-mobile-overlay {
     display: none;
@@ -3330,6 +3369,16 @@ body:has(.rpg-panel.rpg-position-left) #sheld {
         display: flex;
     }
 
+    /* Show the mobile FAB refresh button */
+    .rpg-mobile-refresh {
+        display: flex;
+    }
+
+    /* Hide desktop refresh button on mobile */
+    #rpg-manual-update {
+        display: none !important;
+    }
+
     /* Hide FAB when panel is open */
     body:has(.rpg-panel.rpg-mobile-open) .rpg-mobile-toggle {
         opacity: 0;
@@ -3988,6 +4037,11 @@ body:has(.rpg-panel.rpg-position-left) #sheld {
         font-size: clamp(20px, 5.1vw, 26px) !important;
     }
 
+    /* Larger mobile refresh icon */
+    .rpg-mobile-refresh {
+        font-size: clamp(20px, 5.1vw, 26px) !important;
+    }
+
     /* ========================================
        MOBILE SETTINGS POPUP
        ======================================== */