feat: 审核同名配方智能检测

- 完全相同：提示"已有一模一样的"，不采纳
- 内容不同：显示两个配方成分对比，可选择直接采纳或改名后采纳
- 存为我的只检查个人配方同名

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

frontend/src/components/RecipeDetailOverlay.vue

@@ -621,15 +621,10 @@ async function saveToDiary() {
   }
   const trimmed = name.trim()
   const dupDiary = diaryStore.userDiary.some(d => d.name === trimmed)
-  const dupPublic = recipesStore.recipes.some(r => r.name === trimmed)
   if (dupDiary) {
     ui.showToast('我的配方中已有同名配方「' + trimmed + '」')
     return
   }
-  if (dupPublic) {
-    ui.showToast('公共配方库中已有同名配方「' + trimmed + '」')
-    return
-  }
   try {
     const payload = {
       name: name.trim(),

frontend/src/views/RecipeManager.vue

@@ -1210,7 +1210,46 @@ async function removeRecipe(recipe) {
   }
 }
 
+function recipesIdentical(a, b) {
+  if ((a.ingredients || []).length !== (b.ingredients || []).length) return false
+  const aIngs = [...a.ingredients].sort((x, y) => x.oil.localeCompare(y.oil))
+  const bIngs = [...b.ingredients].sort((x, y) => x.oil.localeCompare(y.oil))
+  return aIngs.every((ing, i) => ing.oil === bIngs[i].oil && ing.drops === bIngs[i].drops)
+}
+
+function formatIngsCompare(ings) {
+  return (ings || []).map(i => `${i.oil} ${i.drops}滴`).join('、')
+}
+
 async function approveRecipe(recipe) {
+  const dup = recipeStore.recipes.find(r => r.name === recipe.name && r._id !== recipe._id)
+  if (dup) {
+    if (recipesIdentical(recipe, dup)) {
+      ui.showToast('公共配方库中已有一模一样的配方「' + recipe.name + '」，无需重复采纳')
+      return
+    }
+    // Different content, show comparison
+    const msg = `公共配方库中已有同名配方「${recipe.name}」但内容不同：\n\n` +
+      `已有：${formatIngsCompare(dup.ingredients)}\n` +
+      `新的：${formatIngsCompare(recipe.ingredients)}\n\n` +
+      `点击"采纳"直接采纳，或"改名"修改新配方名称后采纳`
+    const action = await showConfirm(msg, { okText: '采纳', cancelText: '改名' })
+    if (!action) {
+      // User wants to rename
+      const newName = await showPrompt('请输入新名称：', recipe.name)
+      if (!newName || !newName.trim()) return
+      try {
+        await api(`/api/recipes/${recipe._id}`, {
+          method: 'PUT',
+          body: JSON.stringify({ name: newName.trim() }),
+        })
+        recipe.name = newName.trim()
+      } catch {
+        ui.showToast('改名失败')
+        return
+      }
+    }
+  }
   try {
     const res = await api('/api/recipes/' + recipe._id + '/adopt', { method: 'POST' })
     if (res.ok) {