feat(log): 解耦用户访问日志存储，支持切换日志主库

用户访问日志可在 ClickHouse、PostgreSQL、SQLite 之间切换。
关闭 ClickHouse 时由主库承接写入与查询；切换任务会冻结写入、复制数据后翻转主库。
启动时校验日志主库与运行配置一致，定期清理按各库保留天数删除过期记录。

internal/repository/logstore/cleanup.go

@@ -0,0 +1,93 @@
+// Copyright 2026 Arctel.net
+// SPDX-License-Identifier: Apache-2.0
+
+package logstore
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"strconv"
+	"time"
+
+	"github.com/Rain-kl/Wavelet/internal/model"
+	"github.com/Rain-kl/Wavelet/pkg/logger"
+)
+
+const (
+	defaultLogRetentionDays = 30
+	partitionLeadMonths     = 2
+	userAccessLogTable      = "w_user_access_logs"
+)
+
+// CleanupSummary 汇总本次清理结果。
+type CleanupSummary struct {
+	ActiveDatabase string `json:"active_database"`
+	RetentionDays  int    `json:"retention_days"`
+	Deleted        int64  `json:"deleted"`
+}
+
+// CleanupExpired 按当前日志库保留天数删除过期用户访问日志，并预建 PG 分区。
+func CleanupExpired(ctx context.Context) (CleanupSummary, error) {
+	active, err := ActiveDatabase(ctx)
+	if err != nil {
+		return CleanupSummary{}, err
+	}
+	days := retentionDaysForDatabase(ctx, active)
+	summary := CleanupSummary{ActiveDatabase: active, RetentionDays: days}
+
+	store, err := Active(ctx)
+	if err != nil {
+		return summary, err
+	}
+	now := time.Now().UTC()
+	if err := store.UserAccessLogs.EnsurePartitions(ctx, now, now.AddDate(0, partitionLeadMonths, 0)); err != nil {
+		logger.WarnF(ctx, "logstore: ensure partitions during cleanup failed: %v", err)
+	}
+	cutoff := now.AddDate(0, 0, -days)
+	deleted, err := store.UserAccessLogs.DeleteBefore(ctx, cutoff)
+	if err != nil {
+		return summary, fmt.Errorf("delete expired user access logs: %w", err)
+	}
+	summary.Deleted = deleted
+	return summary, nil
+}
+
+func retentionDaysForDatabase(ctx context.Context, dbName string) int {
+	key := model.ConfigKeyLogRetentionDaysPostgres
+	switch dbName {
+	case dbNameSQLite:
+		key = model.ConfigKeyLogRetentionDaysSQLite
+	case dbNameClickHouse:
+		key = model.ConfigKeyLogRetentionDaysClickHouse
+	}
+	v, err := getConfig(ctx, key)
+	if err != nil {
+		if !errors.Is(err, errConfigReaderNotWired) {
+			logger.ErrorF(ctx, "读取日志保留天数配置失败(key=%s)，回退默认 %d 天: %v", key, defaultLogRetentionDays, err)
+		}
+		return defaultLogRetentionDays
+	}
+	days, perr := strconv.Atoi(v)
+	if perr != nil || days <= 0 {
+		logger.ErrorF(ctx, "日志保留天数配置非法(key=%s, value=%q)，回退默认 %d 天", key, v, defaultLogRetentionDays)
+		return defaultLogRetentionDays
+	}
+	return days
+}
+
+func partitionStatementsRange(from, to time.Time) []string {
+	var out []string
+	start := time.Date(from.Year(), from.Month(), 1, 0, 0, 0, 0, time.UTC)
+	end := time.Date(to.Year(), to.Month(), 1, 0, 0, 0, 0, time.UTC).AddDate(0, 1, 0)
+	for ; start.Before(end); start = start.AddDate(0, 1, 0) {
+		monthEnd := start.AddDate(0, 1, 0)
+		suffix := start.Format("200601")
+		fromDay := start.Format("2006-01-02")
+		toDay := monthEnd.Format("2006-01-02")
+		out = append(out, fmt.Sprintf(
+			"CREATE TABLE IF NOT EXISTS %s_%s PARTITION OF %s FOR VALUES FROM ('%s') TO ('%s')",
+			userAccessLogTable, suffix, userAccessLogTable, fromDay, toDay))
+	}
+	return out
+}