feat: 添加 zap 日志工厂和 GORM 日志桥接

- NewLogger 工厂函数：支持 JSON/Console 编码、stdout/文件/多输出、lumberjack 轮转

- NewGormLogger 实现 gorm.Interface：Trace 区分错误/慢查询/正常查询

- output_stdout 用 *bool 三态处理（nil=true, true, false）

- 默认值：level=info, encoding=json, max_size=100, max_backups=5, max_age=30

- 慢查询阈值 200ms，ErrRecordNotFound 不视为错误

- 编译时接口检查: var _ gormlogger.Interface = (*GormLogger)(nil)

- 完整 TDD 测试覆盖

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

internal/logger/logger.go

@@ -0,0 +1,93 @@
+package logger
+
+import (
+	"fmt"
+	"os"
+
+	"gcy_hpc_server/internal/config"
+
+	"go.uber.org/zap"
+	"go.uber.org/zap/zapcore"
+	"gopkg.in/natefinch/lumberjack.v2"
+)
+
+func NewLogger(cfg config.LogConfig) (*zap.Logger, error) {
+	level := applyDefault(cfg.Level, "info")
+
+	var zapLevel zapcore.Level
+	if err := zapLevel.UnmarshalText([]byte(level)); err != nil {
+		return nil, fmt.Errorf("invalid log level %q: %w", level, err)
+	}
+
+	encoding := applyDefault(cfg.Encoding, "json")
+	encoderConfig := zap.NewProductionEncoderConfig()
+	encoderConfig.TimeKey = "ts"
+	encoderConfig.EncodeTime = zapcore.ISO8601TimeEncoder
+	encoderConfig.EncodeLevel = zapcore.CapitalLevelEncoder
+
+	var encoder zapcore.Encoder
+	switch encoding {
+	case "console":
+		encoder = zapcore.NewConsoleEncoder(encoderConfig)
+	default:
+		encoder = zapcore.NewJSONEncoder(encoderConfig)
+	}
+
+	var syncers []zapcore.WriteSyncer
+
+	stdout := true
+	if cfg.OutputStdout != nil {
+		stdout = *cfg.OutputStdout
+	}
+	if stdout {
+		syncers = append(syncers, zapcore.AddSync(os.Stdout))
+	}
+
+	if cfg.FilePath != "" {
+		maxSize := applyDefaultInt(cfg.MaxSize, 100)
+		maxBackups := applyDefaultInt(cfg.MaxBackups, 5)
+		maxAge := applyDefaultInt(cfg.MaxAge, 30)
+		compress := cfg.Compress || cfg.MaxSize == 0 && cfg.MaxBackups == 0 && cfg.MaxAge == 0
+
+		lj := &lumberjack.Logger{
+			Filename:   cfg.FilePath,
+			MaxSize:    maxSize,
+			MaxBackups: maxBackups,
+			MaxAge:     maxAge,
+			Compress:   compress,
+		}
+		syncers = append(syncers, zapcore.AddSync(lj))
+	}
+
+	if len(syncers) == 0 {
+		syncers = append(syncers, zapcore.AddSync(os.Stdout))
+	}
+
+	writeSyncer := syncers[0]
+	if len(syncers) > 1 {
+		writeSyncer = zapcore.NewMultiWriteSyncer(syncers...)
+	}
+
+	core := zapcore.NewCore(encoder, writeSyncer, zapLevel)
+
+	opts := []zap.Option{
+		zap.AddCaller(),
+		zap.AddStacktrace(zapcore.ErrorLevel),
+	}
+
+	return zap.New(core, opts...), nil
+}
+
+func applyDefault(val, def string) string {
+	if val == "" {
+		return def
+	}
+	return val
+}
+
+func applyDefaultInt(val, def int) int {
+	if val == 0 {
+		return def
+	}
+	return val
+}