feat(server): implement management endpoints and redis sync

Enable full resource management via API and support data plane
synchronization.

- Add CRUD handlers for Providers, Models, and Keys using DTOs
- Implement LogWriter service for asynchronous, batched audit logging
- Update SyncService to snapshot full configuration state to Redis
- Register new API routes and initialize background services
- Add configuration options for logging performance tuning

internal/config/config.go

@@ -3,12 +3,14 @@ package config
 import (
 	"os"
 	"strconv"
+	"time"
 )
 
 type Config struct {
 	Server   ServerConfig
 	Postgres PostgresConfig
 	Redis    RedisConfig
+	Log      LogConfig
 }
 
 type ServerConfig struct {
@@ -25,6 +27,12 @@ type RedisConfig struct {
 	DB       int
 }
 
+type LogConfig struct {
+	BatchSize     int
+	FlushInterval time.Duration
+	QueueCapacity int
+}
+
 func Load() (*Config, error) {
 	return &Config{
 		Server: ServerConfig{
@@ -38,6 +46,11 @@ func Load() (*Config, error) {
 			Password: getEnv("EZ_REDIS_PASSWORD", ""),
 			DB:       getEnvInt("EZ_REDIS_DB", 0),
 		},
+		Log: LogConfig{
+			BatchSize:     getEnvInt("EZ_LOG_BATCH_SIZE", 10),
+			FlushInterval: getEnvDuration("EZ_LOG_FLUSH_MS", 1000),
+			QueueCapacity: getEnvInt("EZ_LOG_QUEUE", 10000),
+		},
 	}, nil
 }
 
@@ -56,3 +69,12 @@ func getEnvInt(key string, fallback int) int {
 	}
 	return fallback
 }
+
+func getEnvDuration(key string, fallbackMs int) time.Duration {
+	if value, ok := os.LookupEnv(key); ok {
+		if i, err := strconv.Atoi(value); err == nil {
+			return time.Duration(i) * time.Millisecond
+		}
+	}
+	return time.Duration(fallbackMs) * time.Millisecond
+}