fix(logger): 修复 caller 字段与 OpsSystemLogSink 停止刷盘

修复点：

- zap logger 不再强制 AddCallerSkip(1)，确保 caller 指向真实调用点

- slog handler 避免重复写 time 字段

- OpsSystemLogSink 优先从字段 component 识别业务组件；停止时 drain 队列并用可用 ctx 刷盘

补充：新增/完善对应单测

backend/internal/pkg/logger/logger.go

@@ -247,7 +247,6 @@ func buildLogger(options InitOptions) (*zap.Logger, zap.AtomicLevel, error) {
 	if stacktraceLevel <= zapcore.FatalLevel {
 		zapOpts = append(zapOpts, zap.AddStacktrace(stacktraceLevel))
 	}
-	zapOpts = append(zapOpts, zap.AddCallerSkip(1))
 
 	logger := zap.New(core, zapOpts...).With(
 		zap.String("service", options.ServiceName),

backend/internal/pkg/logger/logger_test.go

@@ -1,6 +1,7 @@
 package logger
 
 import (
+	"encoding/json"
 	"io"
 	"os"
 	"path/filepath"
@@ -127,3 +128,65 @@ func TestInit_FileOutputFailureDowngrade(t *testing.T) {
 		t.Fatalf("stderr should contain fallback warning, got: %s", string(stderrBytes))
 	}
 }
+
+func TestInit_CallerShouldPointToCallsite(t *testing.T) {
+	origStdout := os.Stdout
+	origStderr := os.Stderr
+	stdoutR, stdoutW, err := os.Pipe()
+	if err != nil {
+		t.Fatalf("create stdout pipe: %v", err)
+	}
+	_, stderrW, err := os.Pipe()
+	if err != nil {
+		t.Fatalf("create stderr pipe: %v", err)
+	}
+	os.Stdout = stdoutW
+	os.Stderr = stderrW
+	t.Cleanup(func() {
+		os.Stdout = origStdout
+		os.Stderr = origStderr
+		_ = stdoutR.Close()
+		_ = stdoutW.Close()
+		_ = stderrW.Close()
+	})
+
+	if err := Init(InitOptions{
+		Level:       "info",
+		Format:      "json",
+		ServiceName: "sub2api",
+		Environment: "test",
+		Caller:      true,
+		Output: OutputOptions{
+			ToStdout: true,
+			ToFile:   false,
+		},
+		Sampling: SamplingOptions{Enabled: false},
+	}); err != nil {
+		t.Fatalf("Init() error: %v", err)
+	}
+
+	L().Info("caller-check")
+	Sync()
+	_ = stdoutW.Close()
+	logBytes, _ := io.ReadAll(stdoutR)
+
+	var line string
+	for _, item := range strings.Split(string(logBytes), "\n") {
+		if strings.Contains(item, "caller-check") {
+			line = item
+			break
+		}
+	}
+	if line == "" {
+		t.Fatalf("log output missing caller-check: %s", string(logBytes))
+	}
+
+	var payload map[string]any
+	if err := json.Unmarshal([]byte(line), &payload); err != nil {
+		t.Fatalf("parse log json failed: %v, line=%s", err, line)
+	}
+	caller, _ := payload["caller"].(string)
+	if !strings.Contains(caller, "logger_test.go:") {
+		t.Fatalf("caller should point to this test file, got: %s", caller)
+	}
+}

backend/internal/pkg/logger/slog_handler.go

@@ -41,8 +41,7 @@ func (h *slogZapHandler) Enabled(_ context.Context, level slog.Level) bool {
 }
 
 func (h *slogZapHandler) Handle(_ context.Context, record slog.Record) error {
-	fields := make([]zap.Field, 0, len(h.attrs)+record.NumAttrs()+4)
-	fields = append(fields, zap.Time("time", record.Time))
+	fields := make([]zap.Field, 0, len(h.attrs)+record.NumAttrs()+3)
 	fields = append(fields, slogAttrsToZapFields(h.groups, h.attrs)...)
 	record.Attrs(func(attr slog.Attr) bool {
 		fields = append(fields, slogAttrToZapField(h.groups, attr))

backend/internal/pkg/logger/slog_handler_test.go

@@ -0,0 +1,90 @@
+package logger
+
+import (
+	"context"
+	"log/slog"
+	"testing"
+	"time"
+
+	"go.uber.org/zap"
+	"go.uber.org/zap/zapcore"
+)
+
+type captureState struct {
+	writes []capturedWrite
+}
+
+type capturedWrite struct {
+	entry  zapcore.Entry
+	fields []zapcore.Field
+}
+
+type captureCore struct {
+	state      *captureState
+	withFields []zapcore.Field
+}
+
+func newCaptureCore() *captureCore {
+	return &captureCore{state: &captureState{}}
+}
+
+func (c *captureCore) Enabled(zapcore.Level) bool {
+	return true
+}
+
+func (c *captureCore) With(fields []zapcore.Field) zapcore.Core {
+	nextFields := make([]zapcore.Field, 0, len(c.withFields)+len(fields))
+	nextFields = append(nextFields, c.withFields...)
+	nextFields = append(nextFields, fields...)
+	return &captureCore{
+		state:      c.state,
+		withFields: nextFields,
+	}
+}
+
+func (c *captureCore) Check(entry zapcore.Entry, ce *zapcore.CheckedEntry) *zapcore.CheckedEntry {
+	return ce.AddCore(entry, c)
+}
+
+func (c *captureCore) Write(entry zapcore.Entry, fields []zapcore.Field) error {
+	allFields := make([]zapcore.Field, 0, len(c.withFields)+len(fields))
+	allFields = append(allFields, c.withFields...)
+	allFields = append(allFields, fields...)
+	c.state.writes = append(c.state.writes, capturedWrite{
+		entry:  entry,
+		fields: allFields,
+	})
+	return nil
+}
+
+func (c *captureCore) Sync() error {
+	return nil
+}
+
+func TestSlogZapHandler_Handle_DoesNotAppendTimeField(t *testing.T) {
+	core := newCaptureCore()
+	handler := newSlogZapHandler(zap.New(core))
+
+	record := slog.NewRecord(time.Date(2026, 1, 1, 12, 0, 0, 0, time.UTC), slog.LevelInfo, "hello", 0)
+	record.AddAttrs(slog.String("component", "http.access"))
+
+	if err := handler.Handle(context.Background(), record); err != nil {
+		t.Fatalf("handle slog record: %v", err)
+	}
+	if len(core.state.writes) != 1 {
+		t.Fatalf("write calls = %d, want 1", len(core.state.writes))
+	}
+
+	var hasComponent bool
+	for _, field := range core.state.writes[0].fields {
+		if field.Key == "time" {
+			t.Fatalf("unexpected duplicate time field in slog adapter output")
+		}
+		if field.Key == "component" {
+			hasComponent = true
+		}
+	}
+	if !hasComponent {
+		t.Fatalf("component field should be preserved")
+	}
+}