feat: 护肤品用ml单位，精油用滴，通过unit字段区分

- 后端: oils表新增unit列(drop/ml)，API返回unit字段
- 前端: 根据unit='ml'显示ml单位，精油显示滴/drop
- 护肤品drop_count改为实际ml容量，成本按用量比例计算
  如玫瑰护手霜100ml ¥135，配方用30ml → 成本¥40.5

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

backend/database.py

@@ -227,6 +227,8 @@ def init_db():
         c.execute("ALTER TABLE oils ADD COLUMN is_active INTEGER DEFAULT 1")
     if "en_name" not in oil_cols:
         c.execute("ALTER TABLE oils ADD COLUMN en_name TEXT DEFAULT ''")
+    if "unit" not in oil_cols:
+        c.execute("ALTER TABLE oils ADD COLUMN unit TEXT DEFAULT 'drop'")
 
     # Migration: add new columns to category_modules if missing
     cat_cols = [row[1] for row in c.execute("PRAGMA table_info(category_modules)").fetchall()]

backend/main.py

@@ -87,6 +87,7 @@ class OilIn(BaseModel):
     retail_price: Optional[float] = None
     en_name: Optional[str] = None
     is_active: Optional[int] = None
+    unit: Optional[str] = None
 
 
 class IngredientIn(BaseModel):
@@ -715,7 +716,7 @@ def impersonate(body: dict, user=Depends(require_role("admin"))):
 @app.get("/api/oils")
 def list_oils():
     conn = get_db()
-    rows = conn.execute("SELECT name, bottle_price, drop_count, retail_price, is_active, en_name FROM oils ORDER BY name").fetchall()
+    rows = conn.execute("SELECT name, bottle_price, drop_count, retail_price, is_active, en_name, unit FROM oils ORDER BY name").fetchall()
     conn.close()
     return [dict(r) for r in rows]
 
@@ -724,11 +725,11 @@ def list_oils():
 def upsert_oil(oil: OilIn, user=Depends(require_role("admin", "senior_editor"))):
     conn = get_db()
     conn.execute(
-        "INSERT INTO oils (name, bottle_price, drop_count, retail_price, en_name, is_active) VALUES (?, ?, ?, ?, ?, ?) "
+        "INSERT INTO oils (name, bottle_price, drop_count, retail_price, en_name, is_active, unit) VALUES (?, ?, ?, ?, ?, ?, ?) "
         "ON CONFLICT(name) DO UPDATE SET bottle_price=excluded.bottle_price, drop_count=excluded.drop_count, "
         "retail_price=excluded.retail_price, en_name=COALESCE(excluded.en_name, oils.en_name), "
-        "is_active=COALESCE(excluded.is_active, oils.is_active)",
+        "is_active=COALESCE(excluded.is_active, oils.is_active), unit=COALESCE(excluded.unit, oils.unit)",
-        (oil.name, oil.bottle_price, oil.drop_count, oil.retail_price, title_case(oil.en_name) if oil.en_name else oil.en_name, oil.is_active),
+        (oil.name, oil.bottle_price, oil.drop_count, oil.retail_price, title_case(oil.en_name) if oil.en_name else oil.en_name, oil.is_active, oil.unit),
     )
     log_audit(conn, user["id"], "upsert_oil", "oil", oil.name, oil.name,
               json.dumps({"bottle_price": oil.bottle_price, "drop_count": oil.drop_count}))

frontend/src/stores/oils.js

@@ -70,6 +70,7 @@ export const useOilsStore = defineStore('oils', () => {
         retailPrice: oil.retail_price ?? null,
         isActive: oil.is_active !== 0,
         enName: oil.en_name ?? null,
+        unit: oil.unit || 'drop',
       }
     }
     oils.value = newOils
@@ -93,18 +94,22 @@ export const useOilsStore = defineStore('oils', () => {
     delete oilsMeta.value[name]
   }
 
-  function isPortionUnit(name) {
+  function isMlUnit(name) {
     const meta = oilsMeta.value[name]
-    return meta && meta.dropCount === 1
+    return meta && meta.unit === 'ml'
+  }
+
+  function isPortionUnit(name) {
+    return isMlUnit(name)
   }
 
   function unitLabel(name, lang = 'zh') {
-    if (isPortionUnit(name)) return lang === 'en' ? 'portion' : '份'
+    if (isMlUnit(name)) return 'ml'
     return lang === 'en' ? 'drop' : '滴'
   }
 
   function unitLabelPlural(name, count, lang = 'zh') {
-    if (isPortionUnit(name)) return lang === 'en' ? (count === 1 ? 'portion' : 'portions') : '份'
+    if (isMlUnit(name)) return 'ml'
     return lang === 'en' ? (count === 1 ? 'drop' : 'drops') : '滴'
   }