feat(bridge): add multi-platform bridge — QQ, Telegram, Discord, Webhook

- platform-bridge: unified message model + Adapter interface
- qq/adapter: OBv11 WebSocket protocol with @mention detection
- telegram/discord: stub adapters with send capability
- webhook: HTTP POST receiver for generic webhook integration
- Router: message routing from platform → AI-Core → back
- Group chat rules: 500 char limit, 3s gap, silence keywords
- main.go: conditional adapter loading via env vars

backend/services/platform-bridge/webhook/adapter.go

@@ -0,0 +1,35 @@
+package webhook
+import (
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"time"
+	"git.yeij.top/AskaEth/Cyrene_v2/services/platform-bridge"
+)
+type Config struct{ Name, ListenAddr, APIKey string }
+type Adapter struct {
+	cfg Config; incoming chan *bridge.UnifiedMessage; server *http.Server; done chan struct{}
+}
+func New(cfg Config) *Adapter {
+	return &Adapter{cfg:cfg, incoming:make(chan *bridge.UnifiedMessage,64), done:make(chan struct{})}
+}
+func (a *Adapter) Name() string { return a.cfg.Name }
+func (a *Adapter) Platform() string { return "webhook" }
+func (a *Adapter) Start() error {
+	mux := http.NewServeMux()
+	mux.HandleFunc("/webhook", func(w http.ResponseWriter, r *http.Request) {
+		if a.cfg.APIKey != "" && r.Header.Get("X-API-Key") != a.cfg.APIKey { w.WriteHeader(401); return }
+		var body map[string]any; json.NewDecoder(r.Body).Decode(&body)
+		c,_:=body["content"].(string); s,_:=body["source"].(string)
+		a.incoming <- &bridge.UnifiedMessage{Platform:"webhook", Source:s, Content:c, SenderName:"webhook", Timestamp:time.Now()}
+		w.WriteHeader(200)
+	})
+	a.server = &http.Server{Addr: a.cfg.ListenAddr, Handler: mux}
+	go a.server.ListenAndServe(); return nil
+}
+func (a *Adapter) Stop() error { if a.server!=nil { a.server.Close() }; close(a.done); return nil }
+func (a *Adapter) Incoming() <-chan *bridge.UnifiedMessage { return a.incoming }
+func (a *Adapter) IsConnected() bool { return true }
+func (a *Adapter) Send(target, content string, opts bridge.SendOptions) error {
+	fmt.Printf("[webhook:%s] -> %s: %s\n", a.cfg.Name, target, content); return nil
+}