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/telegram/adapter.go

@@ -0,0 +1,21 @@
+package telegram
+import (
+	"fmt"
+	"git.yeij.top/AskaEth/Cyrene_v2/services/platform-bridge"
+)
+type Config struct{ Name, Token string }
+type Adapter struct {
+	cfg Config; incoming chan *bridge.UnifiedMessage; 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 "telegram" }
+func (a *Adapter) Start() error { return nil }
+func (a *Adapter) Stop() error { 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("[tg:%s] -> %s: %s\n", a.cfg.Name, target, content); return nil
+}