test: 新增英文搜索单元测试（5个）

- oilEn翻译验证（已知/未知精油）
- 英文查询检测
- 英文匹配精油名和配方en_name

全部通过: 209 unit + 36 e2e

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

frontend/src/__tests__/newFeatures.test.js

@@ -85,3 +85,51 @@ describe('EDITOR_ONLY_TAGS', () => {
     expect(EDITOR_ONLY_TAGS).toContain('已审核')
   })
 })
+
+// ---------------------------------------------------------------------------
+// English search
+// ---------------------------------------------------------------------------
+describe('English search matching', () => {
+  const { oilEn } = require('../composables/useOilTranslation')
+
+  it('oilEn returns English name for known oils', () => {
+    expect(oilEn('薰衣草')).toBe('Lavender')
+    expect(oilEn('茶树')).toBe('Tea Tree')
+    expect(oilEn('乳香')).toBe('Frankincense')
+  })
+
+  it('oilEn returns empty for unknown oils', () => {
+    expect(oilEn('不存在的油')).toBeFalsy()
+  })
+
+  it('English query detection', () => {
+    const isEn = (q) => /^[a-zA-Z\s]+$/.test(q)
+    expect(isEn('lavender')).toBe(true)
+    expect(isEn('Tea Tree')).toBe(true)
+    expect(isEn('薰衣草')).toBe(false)
+    expect(isEn('lav3')).toBe(false)
+  })
+
+  it('English matches oil name in recipe', () => {
+    const recipe = {
+      name: '助眠配方',
+      en_name: 'Sleep Aid Blend',
+      ingredients: [{ oil: '薰衣草', drops: 3 }],
+      tags: []
+    }
+    const q = 'lavender'
+    const isEn = /^[a-zA-Z\s]+$/.test(q)
+    const enNameMatch = isEn && (recipe.en_name || '').toLowerCase().includes(q)
+    const oilEnMatch = isEn && recipe.ingredients.some(ing => (oilEn(ing.oil) || '').toLowerCase().includes(q))
+    expect(oilEnMatch).toBe(true)
+    expect(enNameMatch).toBe(false)
+  })
+
+  it('English matches recipe en_name', () => {
+    const recipe = { name: '助眠', en_name: 'Sleep Aid Blend', ingredients: [], tags: [] }
+    const q = 'sleep'
+    const isEn = /^[a-zA-Z\s]+$/.test(q)
+    const enNameMatch = isEn && (recipe.en_name || '').toLowerCase().includes(q)
+    expect(enNameMatch).toBe(true)
+  })
+})