test(postgres): pgxmock 覆盖 5 个 repo，包级 87.6%

为什么用 pgxmock：testcontainers 需要 docker-in-CI 而当前还没有 CI；
mock 路线 1) 零基础设施 2) 把 SQL 字符串和参数顺序作为契约锁死，
schema 漂移立刻可见——这正是上生产前最需要的信号。pgxmock 升级到
testcontainers 不阻塞 v2，留 v2.1 做 nightly 集成测试。

关键改动：
- internal/repo/persistent/postgres/pool.go：新建 pgxPool 接口，
  列出 5 repo 实际用到的 Begin/Query/Exec 三个方法。生产代码继续
  传 *pgxpool.Pool（自动满足接口），测试传 pgxmock.PgxPoolIface。
- 5 个 repo struct 字段从 *pgxpool.Pool 改为 pgxPool 接口；构造器
  签名保留 *pgxpool.Pool，app.go DI 不动。
- 5 个 *_repo_test.go：每个 repo 至少
  · UpsertMany happy path（精确 SQL + 参数）
  · UpsertMany 跳过逻辑（空字段 / 未收线）
  · UpsertMany ExecError（Rollback 路径）
  · FindRecent happy path（验证 DESC → 反序为升序）
  · FindRecent QueryError
  KlineRepo 额外加了 EmptyShortCircuits 和 BeginError 两个边界。

覆盖率：postgres 包 87.6%（UpsertMany ~86%、FindRecent ~93%）。
New*Repo 构造器为 0% 是设计选择：测试直接构造 struct 避开
*pgxpool.Pool 依赖。

所有 12 条守卫扫过无输出。

internal/repo/persistent/postgres/funding_repo_test.go

@@ -0,0 +1,109 @@
+package postgres
+
+import (
+	"context"
+	"errors"
+	"testing"
+
+	"cryptoHermes/internal/entity"
+
+	"github.com/pashagolub/pgxmock/v4"
+	"github.com/stretchr/testify/require"
+)
+
+func TestFundingRepo_UpsertMany_HappyPath(t *testing.T) {
+	mock, err := pgxmock.NewPool()
+	require.NoError(t, err)
+	defer mock.Close()
+
+	mock.ExpectBegin()
+	mock.ExpectExec("INSERT INTO funding_rates").
+		WithArgs("binance", "BTCUSDT", int64(1700000000000), "0.0001", "50000").
+		WillReturnResult(pgxmock.NewResult("INSERT", 1))
+	mock.ExpectCommit()
+	mock.ExpectRollback()
+
+	r := &FundingRepo{pool: mock}
+	err = r.UpsertMany(context.Background(), []entity.FundingRate{{
+		Source: "binance", Symbol: "BTCUSDT",
+		FundingTime: 1700000000000, FundingRate: "0.0001", MarkPrice: "50000",
+	}})
+	require.NoError(t, err)
+	require.NoError(t, mock.ExpectationsWereMet())
+}
+
+func TestFundingRepo_UpsertMany_SkipsEmptyRate(t *testing.T) {
+	mock, err := pgxmock.NewPool()
+	require.NoError(t, err)
+	defer mock.Close()
+
+	mock.ExpectBegin()
+	mock.ExpectCommit()
+	mock.ExpectRollback()
+
+	r := &FundingRepo{pool: mock}
+	err = r.UpsertMany(context.Background(), []entity.FundingRate{
+		{Symbol: "BTCUSDT", FundingTime: 1, FundingRate: ""}, // 空 rate 跳过
+		{Symbol: "BTCUSDT", FundingTime: 0, FundingRate: "1"}, // 空时间戳跳过
+	})
+	require.NoError(t, err)
+	require.NoError(t, mock.ExpectationsWereMet())
+}
+
+func TestFundingRepo_UpsertMany_ExecError(t *testing.T) {
+	mock, err := pgxmock.NewPool()
+	require.NoError(t, err)
+	defer mock.Close()
+
+	mock.ExpectBegin()
+	mock.ExpectExec("INSERT INTO funding_rates").
+		WithArgs(pgxmock.AnyArg(), pgxmock.AnyArg(), pgxmock.AnyArg(), pgxmock.AnyArg(), pgxmock.AnyArg()).
+		WillReturnError(errors.New("dup key"))
+	mock.ExpectRollback()
+
+	r := &FundingRepo{pool: mock}
+	err = r.UpsertMany(context.Background(), []entity.FundingRate{{
+		Symbol: "BTCUSDT", FundingTime: 1, FundingRate: "0.0001",
+	}})
+	require.Error(t, err)
+	require.Contains(t, err.Error(), "upsert funding")
+	require.NoError(t, mock.ExpectationsWereMet())
+}
+
+func TestFundingRepo_FindRecent_HappyPath(t *testing.T) {
+	mock, err := pgxmock.NewPool()
+	require.NoError(t, err)
+	defer mock.Close()
+
+	rows := mock.NewRows([]string{"source", "symbol", "funding_time", "funding_rate", "mark_price"}).
+		AddRow("binance", "BTCUSDT", int64(2), "0.0002", "50100").
+		AddRow("binance", "BTCUSDT", int64(1), "0.0001", "50000")
+
+	mock.ExpectQuery("SELECT source, symbol, funding_time").
+		WithArgs("BTCUSDT", 100).
+		WillReturnRows(rows)
+
+	r := &FundingRepo{pool: mock}
+	got, err := r.FindRecent(context.Background(), "BTCUSDT", 0) // 0 → 100
+	require.NoError(t, err)
+	require.Len(t, got, 2)
+	// 反序后升序：[1,2]
+	require.Equal(t, int64(1), got[0].FundingTime)
+	require.Equal(t, "50100", got[1].MarkPrice)
+	require.NoError(t, mock.ExpectationsWereMet())
+}
+
+func TestFundingRepo_FindRecent_QueryError(t *testing.T) {
+	mock, err := pgxmock.NewPool()
+	require.NoError(t, err)
+	defer mock.Close()
+
+	mock.ExpectQuery("SELECT source, symbol, funding_time").
+		WithArgs("BTCUSDT", 50).
+		WillReturnError(errors.New("conn closed"))
+
+	r := &FundingRepo{pool: mock}
+	_, err = r.FindRecent(context.Background(), "BTCUSDT", 50)
+	require.Error(t, err)
+	require.NoError(t, mock.ExpectationsWereMet())
+}