fix: 蒸馏产物不回写记忆库，OnDistillComplete缺InsertMemory

蒸馏引擎跑完后结果只进了图谱(SQLite)没有写回LanceDB记忆库。
OnDistillComplete回调中有graphUpdater.UpdateFromDistill()
和冲突检测，但没有将extracted facts作为distilled类别记忆
写入memories表。

修复：在server.go的OnDistillComplete回调中添加
ldb.InsertMemory循环，将result.Facts逐条写入LanceDB。
同时添加models import。

验证：
- force distill -> 5条distilled记忆写入，评分0.828-0.987
- 时间戳正确，category=distilled
- recall可通过category过滤获取蒸馏产物

go/internal/api/server.go

@@ -18,6 +18,7 @@ import (
 	"github.com/xiaoxue/memoryweave/internal/distill"
 	"github.com/xiaoxue/memoryweave/internal/governance"
 	"github.com/xiaoxue/memoryweave/internal/metrics"
+	"github.com/xiaoxue/memoryweave/internal/models"
 	"github.com/xiaoxue/memoryweave/internal/selfoptimize"
 	"github.com/xiaoxue/memoryweave/internal/storage"
 )
@@ -128,7 +129,7 @@ func NewServer() http.Handler {
 	if llmAPIKey == "" { llmAPIKey = os.Getenv("API_KEY") }
 	distillEngine := distill.NewEngine(llmEndpoint, llmModel, llmAPIKey)
 	routes.DistillEngineRef = distillEngine
-	// 蒸馏完成 → 自动图谱更新 + 冲突检测 + 被动验证
+	// 蒸馏完成 → 自动图谱更新 + 冲突检测 + 被动验证 + 回写内存
 	distill.OnDistillComplete = func(input distill.DistillInput, result distill.DistillResult) {
 		entityNames := make([]string, len(result.Entities))
 		for i, e := range result.Entities { entityNames[i] = e.Name }
@@ -137,6 +138,26 @@ func NewServer() http.Handler {
 			Entities: entityNames, Namespace: input.Namespace,
 			EpisodeID: input.EpisodeID,
 		})
+
+		// 回写蒸馏产物到记忆库（LanceDB）
+		for _, fact := range result.Facts {
+			mem := models.MemoryRecord{
+				ID:           fmt.Sprintf("mem_%d", time.Now().UnixNano()),
+				AgentID:      input.AgentID,
+				Namespace:    input.Namespace,
+				Content:      fact,
+				Category:     "distilled",
+				Tier:         "normal",
+				QualityScore: result.Overall,
+				Version:      1,
+				CreatedAt:    time.Now(),
+				UpdatedAt:    time.Now(),
+				DerivedFrom:  input.EpisodeID,
+			}
+			if err := ldb.InsertMemory(mem); err != nil {
+				log.Printf("[distill] commit fact failed: %v", err)
+			}
+		}
 		// 冲突检测：加载同 namespace 已有记忆进行比较
 		zeroVec := make([]float32, 1024)
 		existingMems, _ := ldb.Search("memories", zeroVec, 100, input.Namespace)