feat: 手机保存图片到相册、翻译持久化、预览优化

手机保存图片:
- 使用 navigator.share API（原生分享到相册）
- 桌面端保持下载方式
- 精油知识卡、稀释比例、使用禁忌、配方卡片统一处理

配方卡片预览:
- 预览模式隐藏容量切换按钮，编辑模式保留

英文翻译持久化:
- 修改翻译点击"应用"后，配方英文名保存到 recipes.en_name
- 精油英文名保存到 oils.en_name（通过 saveOil API）
- 精油价目页自动同步（共用 oilsMeta.enName）
- 所有用户打开都能看到修改后的翻译

新增 composables/useSaveImage.js: 统一保存图片工具

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/src/components/RecipeDetailOverlay.vue

@@ -36,8 +36,8 @@
           >English</button>
         </div>
 
-        <!-- Volume selector -->
+        <!-- Volume selector (hidden in preview, only in editor) -->
-        <div class="card-volume-toggle">
+        <div v-if="viewMode === 'editor'" class="card-volume-toggle">
           <button
             v-for="(drops, ml) in VOLUME_DROPS"
             :key="ml"
@@ -583,8 +583,25 @@ async function saveImage() {
     await generateCardImage()
   }
   if (!cardImageUrl.value) return
+  const filename = `${recipe.value.name || '配方'}_配方卡`
+  const isMobile = /iPhone|iPad|iPod|Android/i.test(navigator.userAgent)
+
+  if (isMobile && navigator.canShare) {
+    try {
+      const res = await fetch(cardImageUrl.value)
+      const blob = await res.blob()
+      const file = new File([blob], filename + '.png', { type: 'image/png' })
+      if (navigator.canShare({ files: [file] })) {
+        await navigator.share({ files: [file] })
+        ui.showToast('已保存图片')
+        return
+      }
+    } catch {}
+  }
+
+  // Desktop fallback
   const link = document.createElement('a')
-  link.download = `${recipe.value.name || '配方'}_配方卡.png`
+  link.download = filename + '.png'
   link.href = cardImageUrl.value
   link.click()
   ui.showToast('已保存图片')
@@ -615,18 +632,37 @@ function copyText() {
 
 async function applyTranslation() {
   showTranslationEditor.value = false
-  // Persist en_name to backend
+  let saved = 0
+
+  // 1. Save recipe English name to backend
   if (recipe.value._id && customRecipeNameEn.value) {
     try {
       await api.put(`/api/recipes/${recipe.value._id}`, {
         en_name: customRecipeNameEn.value,
         version: recipe.value._version,
       })
-      ui.showToast('翻译已保存')
+      recipe.value.en_name = customRecipeNameEn.value
-    } catch (e) {
+      saved++
-      ui.showToast('翻译保存失败')
+    } catch {}
-    }
   }
+
+  // 2. Save each oil's English name to backend (updates oils table en_name)
+  for (const [oilName, enName] of Object.entries(customOilNameEn.value)) {
+    if (!enName || !enName.trim()) continue
+    const meta = oilsStore.oilsMeta[oilName]
+    if (!meta) continue
+    // Only save if changed from what's stored
+    if (meta.enName === enName.trim()) continue
+    try {
+      await oilsStore.saveOil(oilName, meta.bottlePrice, meta.dropCount, meta.retailPrice, enName.trim())
+      saved++
+    } catch {}
+  }
+
+  if (saved > 0) {
+    ui.showToast(`翻译已保存（${saved}项）`)
+  }
+
   cardImageUrl.value = null
   nextTick(() => generateCardImage())
 }
@@ -634,7 +670,7 @@ async function applyTranslation() {
 // Override translation getters for card rendering
 function getCardOilName(name) {
   if (cardLang.value === 'en') {
-    return customOilNameEn.value[name] || oilEn(name) || name
+    return customOilNameEn.value[name] || oilsStore.oilsMeta[name]?.enName || oilEn(name) || name
   }
   return name
 }

frontend/src/composables/useSaveImage.js

@@ -0,0 +1,49 @@
+/**
+ * Save a canvas/image — on mobile use native share (save to photos),
+ * on desktop trigger download.
+ */
+export async function saveCanvasImage(canvas, filename) {
+  const isMobile = /iPhone|iPad|iPod|Android/i.test(navigator.userAgent)
+
+  if (isMobile && navigator.canShare) {
+    // Mobile: use native share sheet → save to photos
+    try {
+      const blob = await new Promise(r => canvas.toBlob(r, 'image/png'))
+      const file = new File([blob], filename + '.png', { type: 'image/png' })
+      if (navigator.canShare({ files: [file] })) {
+        await navigator.share({ files: [file] })
+        return true
+      }
+    } catch {}
+  }
+
+  // Desktop fallback: direct download
+  const url = canvas.toDataURL('image/png')
+  const a = document.createElement('a')
+  a.href = url
+  a.download = filename + '.png'
+  a.click()
+  return true
+}
+
+/**
+ * Capture an element as image and save it.
+ */
+export async function captureAndSave(element, filename) {
+  const { default: html2canvas } = await import('html2canvas')
+  // Hide buttons during capture
+  const buttons = element.querySelectorAll('button')
+  buttons.forEach(b => b.style.display = 'none')
+  try {
+    const canvas = await html2canvas(element, {
+      scale: 2,
+      backgroundColor: '#ffffff',
+      useCORS: true,
+    })
+    buttons.forEach(b => b.style.display = '')
+    return saveCanvasImage(canvas, filename)
+  } catch {
+    buttons.forEach(b => b.style.display = '')
+    return false
+  }
+}

frontend/src/views/OilReference.vue

@@ -725,26 +725,18 @@ function exportPDF() {
   setTimeout(() => w.print(), 500)
 }
 
-// Save modal as image using html2canvas
+// Save modal as image
 async function saveModalImage(name) {
+  const overlay = document.querySelector('.modal-overlay')
+  if (!overlay) return
+  const cardEl = overlay.querySelector('[style*="border-radius: 20px"], [style*="border-radius:20px"]') ||
+                 overlay.querySelector('.oil-card-modal') || overlay.children[0]
+  if (!cardEl) return
   try {
-    const { default: html2canvas } = await import('html2canvas')
+    const { captureAndSave } = await import('../composables/useSaveImage')
-    const overlay = document.querySelector('.modal-overlay')
+    const ok = await captureAndSave(cardEl, name || '精油知识卡')
-    if (!overlay) return
+    if (ok) ui.showToast('图片已保存')
-    const cardEl = overlay.querySelector('[style*="border-radius: 20px"], [style*="border-radius:20px"]') || overlay.children[0]
+  } catch {
-    if (!cardEl) return
-    // Hide close buttons during capture
-    const btns = cardEl.querySelectorAll('button')
-    btns.forEach(b => b.style.display = 'none')
-    const canvas = await html2canvas(cardEl, { scale: 2, backgroundColor: '#ffffff', useCORS: true })
-    btns.forEach(b => b.style.display = '')
-    const url = canvas.toDataURL('image/png')
-    const a = document.createElement('a')
-    a.href = url
-    a.download = (name || '精油知识卡') + '.png'
-    a.click()
-    ui.showToast('图片已保存')
-  } catch (e) {
     ui.showToast('保存失败')
   }
 }