Version: 0.9.76.dev.260505

后端：
1.阶段 6 agent / memory 服务化收口
- 新增 cmd/agent 独立进程入口，承载 agent zrpc server、agent outbox relay / consumer 和运行时依赖初始化
- 补齐 services/agent/rpc 的 Chat stream 与 conversation meta/list/timeline、schedule-preview、context-stats、schedule-state unary RPC
- 新增 gateway/client/agent 与 shared/contracts/agent，将 /api/v1/agent chat 和非 chat 门面切到 agent zrpc
- 收缩 gateway 本地 AgentService 装配，双 RPC 开关开启时不再初始化本地 agent 编排、LLM、RAG 和 memory reader fallback
- 将 backend/memory 物理迁入 services/memory，私有实现收入 internal，保留 module/model/observe 作为 memory 服务门面
- 调整 memory outbox、memory reader 和 agent 记忆渲染链路的 import 与服务边界，cmd/memory 独占 memory worker / consumer
- 关闭 gateway 侧 agent outbox worker 所有权，agent relay / consumer 由 cmd/agent 独占，gateway 仅保留 HTTP/SSE 门面与迁移期开关回退
- 更新阶段 6 文档，记录 agent / memory 当前切流点、smoke 结果，以及 backend/client 与 gateway/shared 的目录收口口径

backend/services/memory/observe/metrics.go

@@ -0,0 +1,158 @@
+package observe
+
+import (
+	"sort"
+	"strings"
+	"sync"
+)
+
+// CounterSnapshot 是轻量计数器的快照视图，供后续排障或接平台时读取。
+type CounterSnapshot struct {
+	Name   string
+	Labels map[string]string
+	Value  int64
+}
+
+// MetricsRecorder 描述 memory 模块对计数器的最小依赖。
+type MetricsRecorder interface {
+	AddCounter(name string, delta int64, labels map[string]string)
+	Snapshot() []CounterSnapshot
+}
+
+// NewNopMetrics 返回空实现，保证无观测平台时仍可安全运行。
+func NewNopMetrics() MetricsRecorder {
+	return nopMetrics{}
+}
+
+type nopMetrics struct{}
+
+func (nopMetrics) AddCounter(string, int64, map[string]string) {}
+
+func (nopMetrics) Snapshot() []CounterSnapshot {
+	return nil
+}
+
+// MetricsRegistry 是 memory 模块当前阶段的轻量内存计数器实现。
+//
+// 职责边界：
+// 1. 只做线程安全计数，不负责导出协议；
+// 2. 标签做低基数归一化，避免治理期临时字段把指标打爆；
+// 3. 后续若项目统一接 Prometheus，可直接保留调用口径并替换实现。
+type MetricsRegistry struct {
+	mu       sync.RWMutex
+	counters map[string]*counterRecord
+}
+
+type counterRecord struct {
+	name   string
+	labels map[string]string
+	value  int64
+}
+
+func NewMetricsRegistry() *MetricsRegistry {
+	return &MetricsRegistry{
+		counters: make(map[string]*counterRecord),
+	}
+}
+
+// AddCounter 追加计数值；delta<=0 时直接忽略，避免脏数据污染快照。
+func (r *MetricsRegistry) AddCounter(name string, delta int64, labels map[string]string) {
+	if r == nil || delta <= 0 {
+		return
+	}
+
+	name = strings.TrimSpace(name)
+	if name == "" {
+		return
+	}
+	normalizedLabels := normalizeLabels(labels)
+	key := buildCounterKey(name, normalizedLabels)
+
+	r.mu.Lock()
+	defer r.mu.Unlock()
+	if existing, ok := r.counters[key]; ok {
+		existing.value += delta
+		return
+	}
+	r.counters[key] = &counterRecord{
+		name:   name,
+		labels: normalizedLabels,
+		value:  delta,
+	}
+}
+
+// Snapshot 返回当前全部计数器快照，便于后续排障或测试读取。
+func (r *MetricsRegistry) Snapshot() []CounterSnapshot {
+	if r == nil {
+		return nil
+	}
+
+	r.mu.RLock()
+	defer r.mu.RUnlock()
+	if len(r.counters) == 0 {
+		return nil
+	}
+
+	keys := make([]string, 0, len(r.counters))
+	for key := range r.counters {
+		keys = append(keys, key)
+	}
+	sort.Strings(keys)
+
+	result := make([]CounterSnapshot, 0, len(keys))
+	for _, key := range keys {
+		record := r.counters[key]
+		labels := make(map[string]string, len(record.labels))
+		for labelKey, labelValue := range record.labels {
+			labels[labelKey] = labelValue
+		}
+		result = append(result, CounterSnapshot{
+			Name:   record.name,
+			Labels: labels,
+			Value:  record.value,
+		})
+	}
+	return result
+}
+
+func normalizeLabels(labels map[string]string) map[string]string {
+	if len(labels) == 0 {
+		return nil
+	}
+
+	result := make(map[string]string, len(labels))
+	for key, value := range labels {
+		key = strings.TrimSpace(key)
+		value = strings.TrimSpace(value)
+		if key == "" || value == "" {
+			continue
+		}
+		result[key] = value
+	}
+	if len(result) == 0 {
+		return nil
+	}
+	return result
+}
+
+func buildCounterKey(name string, labels map[string]string) string {
+	if len(labels) == 0 {
+		return name
+	}
+
+	keys := make([]string, 0, len(labels))
+	for key := range labels {
+		keys = append(keys, key)
+	}
+	sort.Strings(keys)
+
+	var sb strings.Builder
+	sb.WriteString(name)
+	for _, key := range keys {
+		sb.WriteString("|")
+		sb.WriteString(key)
+		sb.WriteString("=")
+		sb.WriteString(labels[key])
+	}
+	return sb.String()
+}