refactor(api): replace AssetRefWriter with goroutine for stateless asset ref increments (#470)

Remove the Redis-buffered AssetRefWriter package entirely and replace it
with a simple goroutine fire-and-forget in StoreMessage. This makes the
API server fully stateless — no background goroutine, no Start/Close
lifecycle, no Redis buffering layer.

Author: GenerQAQ

src/server/api/go/cmd/server/main.go

@@ -24,7 +24,6 @@ import (
 	"github.com/gin-gonic/gin"
 	"github.com/memodb-io/Acontext/internal/bootstrap"
 	"github.com/memodb-io/Acontext/internal/config"
-	"github.com/memodb-io/Acontext/internal/infra/assetrefwriter"
 	"github.com/memodb-io/Acontext/internal/infra/cache"
 	dbpkg "github.com/memodb-io/Acontext/internal/infra/db"
 	"github.com/memodb-io/Acontext/internal/modules/handler"
@@ -141,12 +140,5 @@ func main() {
 		log.Sugar().Errorw("server shutdown", "err", err)
 	}
 
-	// Flush buffered asset reference writes before exit
-	if writer := do.MustInvoke[*assetrefwriter.AssetRefWriter](inj); writer != nil {
-		if err := writer.Close(ctx); err != nil {
-			log.Sugar().Errorw("asset ref writer shutdown", "err", err)
-		}
-	}
-
 	log.Sugar().Info("server exited")
 }

src/server/api/go/internal/bootstrap/container.go

@@ -9,7 +9,6 @@ import (
 
 	"github.com/memodb-io/Acontext/configs"
 	"github.com/memodb-io/Acontext/internal/config"
-	"github.com/memodb-io/Acontext/internal/infra/assetrefwriter"
 	"github.com/memodb-io/Acontext/internal/infra/blob"
 	"github.com/memodb-io/Acontext/internal/infra/cache"
 	"github.com/memodb-io/Acontext/internal/infra/db"
@@ -217,26 +216,6 @@ func BuildContainer() *do.Injector {
 		), nil
 	})
 
-	// AssetRefWriter — buffers asset reference increments in Redis for async batch flush
-	do.Provide(inj, func(i *do.Injector) (*assetrefwriter.AssetRefWriter, error) {
-		cfg := do.MustInvoke[*config.Config](i)
-		if !cfg.AssetRefWriter.Enabled {
-			return nil, nil
-		}
-		interval := time.Duration(cfg.AssetRefWriter.FlushIntervalMs) * time.Millisecond
-		if interval <= 0 {
-			interval = time.Second
-		}
-		w := assetrefwriter.New(
-			do.MustInvoke[*redis.Client](i),
-			do.MustInvoke[repo.AssetReferenceRepo](i),
-			do.MustInvoke[*zap.Logger](i),
-			assetrefwriter.WithFlushInterval(interval),
-		)
-		w.Start()
-		return w, nil
-	})
-
 	do.Provide(inj, func(i *do.Injector) (repo.SessionRepo, error) {
 		return repo.NewSessionRepo(
 			do.MustInvoke[*gorm.DB](i),
@@ -290,7 +269,6 @@ func BuildContainer() *do.Injector {
 			do.MustInvoke[repo.SessionRepo](i),
 			do.MustInvoke[repo.SessionEventRepo](i),
 			do.MustInvoke[repo.AssetReferenceRepo](i),
-			do.MustInvoke[*assetrefwriter.AssetRefWriter](i),
 			do.MustInvoke[*zap.Logger](i),
 			do.MustInvoke[*blob.S3Deps](i),
 			do.MustInvoke[*mq.Publisher](i),

src/server/api/go/internal/config/config.go

@@ -101,25 +101,19 @@ type ArtifactCfg struct {
 	MaxUploadSizeBytes int64 // Maximum file upload size in bytes
 }
 
-type AssetRefWriterCfg struct {
-	Enabled         bool // Enable async buffered writes for asset references (default true)
-	FlushIntervalMs int  // Flush interval in milliseconds (default 1000)
-}
-
 type Config struct {
-	App            AppCfg
-	Root           RootCfg
-	Log            LogCfg
-	Database       DBCfg
-	Redis          RedisCfg
-	RabbitMQ       MQCfg
-	S3             S3Cfg
-	Core           CoreCfg
-	Metrics        MetricsCfg
-	Telemetry      TelemetryCfg
-	Supabase       SupabaseCfg
-	Artifact       ArtifactCfg
-	AssetRefWriter AssetRefWriterCfg
+	App       AppCfg
+	Root      RootCfg
+	Log       LogCfg
+	Database  DBCfg
+	Redis     RedisCfg
+	RabbitMQ  MQCfg
+	S3        S3Cfg
+	Core      CoreCfg
+	Metrics   MetricsCfg
+	Telemetry TelemetryCfg
+	Supabase  SupabaseCfg
+	Artifact  ArtifactCfg
 }
 
 func setDefaults(v *viper.Viper) {
@@ -157,8 +151,6 @@ func setDefaults(v *viper.Viper) {
 	v.SetDefault("supabase.apiKey", "")
 	v.SetDefault("supabase.authURL", "")
 	v.SetDefault("artifact.maxUploadSizeBytes", 16777216) // Default 16MB (16 * 1024 * 1024 bytes)
-	v.SetDefault("assetRefWriter.enabled", true)
-	v.SetDefault("assetRefWriter.flushIntervalMs", 1000)
 }
 
 func Load() (*Config, error) {