feat(runtime+admin): A2 LLM异步提取接线 + A4 Tracing接线 + A6通知后端聚合

A2 异步记忆提取:
- loop/memory.go: asyncExtractor接口(ExtractAsync)+extractMemoryAsync(60s超时,WithOutCancel,dispatch即返回,后台落库,失败仅Warn)+persistMemories共用
- run.go 三个回合落定点改异步提取; 删除run.go逐步提取(design/03'每轮后', 避免多轮工具N次LLM调用/重复写)
- cmd/cyrene/extractor.go buildMemoryExtractor: llmGroupUsable为真→LLMExtractor, 否则回落ManualExtractor(日志说明); keylessEndpoint放行loopback/私网

A4 可观测性 Tracing:
- cmd/cyrene/observability.go: newAppTraceWriter+traceFanout(多sink)+gatewaySpanSink(走gw.ObserveSpan,喂环形缓冲+LLM/subagent指标)
- wire.go 注入; 未改trace/gateway数据结构

A6 通知后端:
- internal/services/gateway/notifications.go(311行): GET /admin/notifications?type=&before=&limit= (adminAuth)
- 聚合已有源(obs.audit SQLite + s.backthink), createdAt倒序, id=source:id; 类型派生(channel/system/audit/backthink); 无新建表/无新Deps/wire零改动
- 诚实: backthink仅shouldPush计, 未注入源为空, 报错500, 未读游标后置
- 契约与前端Y一致: {id,type,title,body,source,createdAt}, before含游标(<=), type未知400
- Docs/api-client v0.33

全仓 build/vet/test绿(56包)+win/darwin/linux-arm64交叉编译绿; 新增测试(memory_async/extractor/observability/notifications)

cmd/cyrene/observability_test.go

@@ -0,0 +1,164 @@
+package main
+
+import (
+	"context"
+	"encoding/json"
+	"io"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+	"time"
+
+	"git.yeij.top/AskaEth/Cyrene_v2/internal/auth"
+	"git.yeij.top/AskaEth/Cyrene_v2/internal/config"
+	"git.yeij.top/AskaEth/Cyrene_v2/internal/runtime/trace"
+	"git.yeij.top/AskaEth/Cyrene_v2/internal/services/gateway"
+)
+
+const obsTestSecret = "0123456789abcdef0123456789abcdef"
+
+// recordingWriter captures the spans a fanout hands it.
+type recordingWriter struct {
+	spans []trace.SpanRecord
+}
+
+func (r *recordingWriter) WriteSpan(rec trace.SpanRecord) error {
+	r.spans = append(r.spans, rec)
+	return nil
+}
+
+// TestTraceFanout_LateSinkReceivesSpans proves the composition root can register
+// a sink after the loop's tracer is already running: spans finished before the
+// sink is added do not reach it, every span after does (the gateway is built
+// after the loop, so this ordering is what A4 depends on).
+func TestTraceFanout_LateSinkReceivesSpans(t *testing.T) {
+	t.Parallel()
+	early := &recordingWriter{}
+	fanout := newTraceFanout(early)
+	tracer := trace.New(fanout)
+
+	_, first := tracer.StartSpan(context.Background(), "before", trace.SpanKindStateTransition)
+	first.Finish(trace.SpanStatusOK)
+
+	late := &recordingWriter{}
+	fanout.Add(late)
+
+	_, second := tracer.StartSpan(context.Background(), "after", trace.SpanKindLLM)
+	second.Finish(trace.SpanStatusOK)
+
+	if len(early.spans) != 2 {
+		t.Fatalf("early sink spans = %d, want 2", len(early.spans))
+	}
+	if len(late.spans) != 1 || late.spans[0].ID != second.ID {
+		t.Fatalf("late sink spans = %+v, want exactly the span %q", late.spans, second.ID)
+	}
+}
+
+// TestWireGatewayTraceSink_Guards proves the boot helper tolerates a missing
+// tracer or gateway, so a degraded boot cannot panic on the observability path.
+func TestWireGatewayTraceSink_Guards(t *testing.T) {
+	t.Parallel()
+	wireGatewayTraceSink(&app{log: testLog()}, nil)
+	a := &app{log: testLog(), traceWriter: newAppTraceWriter()}
+	wireGatewayTraceSink(a, nil)
+	if len(a.traceWriter.writers) != 1 {
+		t.Fatalf("writers = %d, want 1 (the stderr recorder only)", len(a.traceWriter.writers))
+	}
+}
+
+// TestGatewaySpanSink_FeedsTraceEndpointAndMetrics is the A4 acceptance: a span
+// emitted by the tracer is written through the gateway sink (registered by the
+// same helpers wire.go calls) and surfaces both in
+// GET /api/v1/admin/observability/trace (a real span, not an empty buffer) and in
+// the LLM metric counter.
+func TestGatewaySpanSink_FeedsTraceEndpointAndMetrics(t *testing.T) {
+	t.Parallel()
+	jwt := auth.New(config.AuthConfig{JWTSecret: obsTestSecret})
+	gw, err := gateway.New(&config.Config{}, gateway.Deps{Log: testLog(), Auth: jwt})
+	if err != nil {
+		t.Fatalf("gateway.New: %v", err)
+	}
+	t.Cleanup(gw.Close)
+	ts := httptest.NewServer(gw.Handler())
+	t.Cleanup(ts.Close)
+
+	// Exactly the boot path: the app's fanout is built in wireRuntime and the
+	// gateway sink is registered in wireFrontend.
+	a := &app{log: testLog(), traceWriter: newAppTraceWriter()}
+	wireGatewayTraceSink(a, gw)
+	tracer := trace.New(a.traceWriter)
+
+	ctx := context.Background()
+	_, llmSpan := tracer.StartSpan(ctx, "llm.chat", trace.SpanKindLLM)
+	llmSpan.Finish(trace.SpanStatusOK)
+	_, stepSpan := tracer.StartSpan(ctx, "loop.step", trace.SpanKindStateTransition)
+	_ = stepSpan.SetProp("session", "web")
+	stepSpan.Finish(trace.SpanStatusOK)
+
+	tok, err := jwt.Sign("acct", auth.RoleOwner, time.Hour)
+	if err != nil {
+		t.Fatalf("sign token: %v", err)
+	}
+
+	var traceBody struct {
+		Data []struct {
+			ID   string `json:"id"`
+			Name string `json:"name"`
+			Kind string `json:"kind"`
+		} `json:"data"`
+	}
+	status, raw := obsGet(t, ts.URL+"/api/v1/admin/observability/trace", tok)
+	if status != http.StatusOK {
+		t.Fatalf("trace status = %d, want 200 (body=%s)", status, raw)
+	}
+	if err := json.Unmarshal(raw, &traceBody); err != nil {
+		t.Fatalf("decode trace: %v (body=%s)", err, raw)
+	}
+	seen := map[string]string{}
+	for _, sp := range traceBody.Data {
+		seen[sp.ID] = sp.Kind
+	}
+	if seen[stepSpan.ID] != string(trace.SpanKindStateTransition) {
+		t.Fatalf("trace endpoint = %+v, want the loop.step span %q", traceBody.Data, stepSpan.ID)
+	}
+	if seen[llmSpan.ID] != string(trace.SpanKindLLM) {
+		t.Fatalf("trace endpoint = %+v, want the llm span %q", traceBody.Data, llmSpan.ID)
+	}
+
+	var metricsBody struct {
+		Data struct {
+			LLMCalls int64 `json:"llmCalls"`
+		} `json:"data"`
+	}
+	status, raw = obsGet(t, ts.URL+"/api/v1/admin/observability/metrics", tok)
+	if status != http.StatusOK {
+		t.Fatalf("metrics status = %d, want 200 (body=%s)", status, raw)
+	}
+	if err := json.Unmarshal(raw, &metricsBody); err != nil {
+		t.Fatalf("decode metrics: %v (body=%s)", err, raw)
+	}
+	if metricsBody.Data.LLMCalls != 1 {
+		t.Fatalf("llmCalls = %d, want 1 (ObserveSpan counts the emitted llm span)", metricsBody.Data.LLMCalls)
+	}
+}
+
+// obsGet performs an authenticated owner GET and returns the status plus the raw
+// body.
+func obsGet(t *testing.T, url, token string) (int, []byte) {
+	t.Helper()
+	req, err := http.NewRequest(http.MethodGet, url, nil)
+	if err != nil {
+		t.Fatalf("new request: %v", err)
+	}
+	req.Header.Set("Authorization", "Bearer "+token)
+	resp, err := http.DefaultClient.Do(req)
+	if err != nil {
+		t.Fatalf("GET %s: %v", url, err)
+	}
+	defer resp.Body.Close()
+	raw, err := io.ReadAll(resp.Body)
+	if err != nil {
+		t.Fatalf("read %s: %v", url, err)
+	}
+	return resp.StatusCode, raw
+}