perfsprint 18→0：strconv.Itoa/FormatInt/FormatUint/FormatBool 替代 fmt.Sprintf、无动词 fmt.Errorf→errors.New、纯字符串拼接。全部语义等价（已核对 diff）。修正 fixer 遗留的 import 问题（引入 goimports 统一整理）。

Result: {"status":"keep","total_issues":56,"golint_canonicalheader":8,"golint_errname":1,"golint_errorlint":12,"golint_forcetypeassert":3,"golint_gosec":0,"golint_intrange":3,"golint_modernize":5,"golint_nilnil":3,"golint_perfsprint":0,"golint_prealloc":3,"golint_recvcheck":7,"golint_usestdlibvars":3,"golint_wastedassign":7,"golint_total":55,"eslint_problems":1,"eslint_errors":0,"eslint_warnings":1,"tsc_errors":0,"measure_s":47}

internal/repository/analytics/node_observability_writer.go

@@ -5,6 +5,7 @@ package analytics
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"strings"
 	"time"
@@ -30,7 +31,7 @@ func BatchInsertNodeMetricSnapshots(ctx context.Context, snapshots []analyticsmo
 		return nil
 	}
 	if db.ChConn == nil {
-		return fmt.Errorf("clickhouse connection is not initialized")
+		return errors.New("clickhouse connection is not initialized")
 	}
 
 	batch, err := db.ChConn.PrepareBatch(ctx, analyticsmodel.NodeMetricSnapshot{}.BatchInsertSQL())
@@ -102,7 +103,7 @@ func BatchInsertNodeEdgeHealth(ctx context.Context, rows []analyticsmodel.NodeEd
 		return nil
 	}
 	if db.ChConn == nil {
-		return fmt.Errorf("clickhouse connection is not initialized")
+		return errors.New("clickhouse connection is not initialized")
 	}
 	batch, err := db.ChConn.PrepareBatch(ctx, analyticsmodel.NodeEdgeHealth{}.BatchInsertSQL())
 	if err != nil {
@@ -160,7 +161,7 @@ func BatchInsertNodeObsFrps(ctx context.Context, observations []analyticsmodel.N
 		return nil
 	}
 	if db.ChConn == nil {
-		return fmt.Errorf("clickhouse connection is not initialized")
+		return errors.New("clickhouse connection is not initialized")
 	}
 
 	batch, err := db.ChConn.PrepareBatch(ctx, analyticsmodel.NodeObsFrps{}.BatchInsertSQL())
@@ -223,7 +224,7 @@ func BatchInsertNodeObsFrpc(ctx context.Context, observations []analyticsmodel.N
 		return nil
 	}
 	if db.ChConn == nil {
-		return fmt.Errorf("clickhouse connection is not initialized")
+		return errors.New("clickhouse connection is not initialized")
 	}
 
 	batch, err := db.ChConn.PrepareBatch(ctx, analyticsmodel.NodeObsFrpc{}.BatchInsertSQL())