feat: complete OpenClaw plugin API bridge with async notification architecture

- simulator/main.js: All 30+ register* methods now send JSON-RPC notifications
  to Go instead of being silent no-ops. Each plugin capability registration
  (tool, provider, channel, hook, http_route, command, service, etc.) is
  forwarded to Go via the notify channel.

- sidecar.go: Refactored to async reader goroutine. Single goroutine reads
  all stdout lines, routes responses to pending callers via channel by ID,
  and dispatches notifications (no-ID messages) to notifyCh for handling.

- plugin.go: drainNotify() collects all capabilities registered during
  plugin init. handleNotify() logs each registered capability for visibility.

- All 9 openclaw tests pass including simulator + full pipeline tests.

internal/plugins/openclaw/plugin.go

@@ -142,6 +142,9 @@ func (p *Plugin) loadOCPlugin(s *sdk.PluginSDK, dir, name string) error {
 		return nil
 	}
 
+	// 收集插件注册过程中模拟器推送的通知
+	p.drainNotify(sp, name)
+
 	tools, err := sp.ListTools()
 	if err != nil {
 		sp.Close()
@@ -174,6 +177,37 @@ func (p *Plugin) loadOCPlugin(s *sdk.PluginSDK, dir, name string) error {
 	return nil
 }
 
+func (p *Plugin) drainNotify(sp *sidecarProcess, name string) {
+	for {
+		select {
+		case n := <-sp.NotifyChan():
+			p.handleNotify(n, name)
+		default:
+			return
+		}
+	}
+}
+
+func (p *Plugin) handleNotify(n OCNotification, name string) {
+	if n.Method != "register" {
+		log.Printf("[openclaw] ocplugin %s: unknown notify method: %s", name, n.Method)
+		return
+	}
+	var params struct {
+		Type string          `json:"type"`
+		Data json.RawMessage `json:"data"`
+	}
+	if err := json.Unmarshal(n.Params, &params); err != nil {
+		log.Printf("[openclaw] ocplugin %s: bad notify params: %v", name, err)
+		return
+	}
+	dataStr := string(params.Data)
+	if len(dataStr) > 200 {
+		dataStr = dataStr[:200] + "..."
+	}
+	log.Printf("[openclaw] ocplugin %s: capability %s data=%s", name, params.Type, dataStr)
+}
+
 func (p *Plugin) loadSidecar(s *sdk.PluginSDK, dir, name string) error {
 	sp, err := launchSidecar(dir, name)
 	if err != nil {