feat(backend): 出入库编码搜索双路匹配+建单填快照；finance 趋势/日期区间；partner/product 拼音搜索

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01JJ1g8XV1YhhmHRzhwWEW7o

backend/internal/handler/product_test.go

@@ -66,6 +66,30 @@ func TestProductHandler_CRUD(t *testing.T) {
 	assert.Equal(t, float64(0), resp["total"].(float64))
 }
 
+// 拼音搜索（原型口径：商品名 / 拼音 / 编码）：List keyword 匹配 name_pinyin/name_initials
+func TestProductHandler_List_PinyinSearch(t *testing.T) {
+	db := testutil.SetupTestDB()
+	shop := testutil.CreateTestShop(db, "PROD_PY")
+	user := testutil.CreateTestUser(db, shop.ID, "admin", "pass", "admin")
+	token := getAuthToken(user.ID, shop.ID, "admin")
+	r := setupProtectedRouter(db)
+
+	w := makeRequest(r, "POST", "/api/v1/products", token, map[string]interface{}{
+		"name": "飞天茅台", "code": "MT-FT-500", "unit": "件",
+	})
+	require.Equal(t, http.StatusCreated, w.Code)
+
+	for kw, want := range map[string]float64{
+		"feitian": 1, // 全拼
+		"ftmt":    1, // 首字母
+		"MT-FT":   1, // 编码
+		"wuliang": 0,
+	} {
+		w := makeRequest(r, "GET", "/api/v1/products?keyword="+kw, token, nil)
+		assert.Equal(t, want, parseResponse(w)["total"].(float64), "keyword=%s", kw)
+	}
+}
+
 func TestProductHandler_HotelIsolation(t *testing.T) {
 	db := testutil.SetupTestDB()