fix(pwa): 修正 iOS 工具列按鈕需點兩下才反應的問題

使用 onTouchEnd + preventDefault() 讓按鈕在 touchEnd 立即觸發，
繞過 iOS Safari 在 epub iframe 有焦點時「第一次觸控消化焦點」的行為。
同時加入 touch-action: manipulation 移除 300ms 雙擊延遲。

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: Retsomm

pwa/src/components/Reader.tsx

@@ -1611,7 +1611,9 @@ const Reader = ({ bookPath, bookId, bookRecord, getCoverDataUrl, onBack, darkMod
                     fontFamily: '"JetBrains Mono", ui-monospace, monospace', letterSpacing: '0.06em',
                     borderBottom: `2px solid ${mobilePanelTab === key ? 'oklch(0.62 0.14 40)' : 'transparent'}`,
                     color: mobilePanelTab === key ? 'oklch(0.62 0.14 40)' : (darkMode ? '#7a706a' : '#9a8f80'),
+                    touchAction: 'manipulation',
                   }}
+                  onTouchEnd={(e) => { e.preventDefault(); setMobilePanelTab(key) }}
                   onClick={() => setMobilePanelTab(key)}
                 >
                   {label}

pwa/src/components/Toolbar.tsx

@@ -127,10 +127,12 @@ const Toolbar = ({
         color: isActive ? accentCol : ink3Col,
         background: isActive ? accentBg : 'transparent',
         display: 'flex', alignItems: 'center', justifyContent: 'center', flexShrink: 0,
+        touchAction: 'manipulation',
         ...extraStyle,
       }}
       onMouseEnter={(e) => { if (!isActive) e.currentTarget.style.background = hoverBg }}
       onMouseLeave={(e) => { e.currentTarget.style.background = isActive ? accentBg : 'transparent' }}
+      onTouchEnd={(e) => { e.preventDefault(); onClick() }}
       onClick={onClick}
       aria-label={ariaLabel}
       title={ariaLabel}