feat(backthink): 事件驱动主动消息绕过PushGate——IoT等事件该发就发(heartbeat仍受60min节流)

- trigger.go: 新增 TriggerKind(TriggerHeartbeat/TriggerEvent) + Trigger.Kind 标记触发来源
- push.go: PushRequest.TriggerKind 分流——event 跳过 gate.Allow/RecordPush(该发就发)，heartbeat 仍受 60min≤1/冷却/分类限频；PushResult.Bypassed 标记 + detail=event_bypass 区分
- backthink.go: think() 传 TriggerKind + 过同事件去重门
- event_dedup.go(新): 同事件(Source+Summary)去重防刷，无 60min 节流；不同事件/心跳后重置链
- 测试: event 连续 3 次全推 bypass / heartbeat 第2次 rate_limited / event 不消耗心跳限 / 同事件去重
- build/vet/test 全绿 + windows/darwin 交叉编译通过

internal/services/backthink/push.go

@@ -50,6 +50,10 @@ type PushResult struct {
 	Pushed bool
 	// Route is the delivery route taken.
 	Route Route
+	// Bypassed reports whether this push was event-driven and skipped the PushGate
+	// (a real event, "该发就发"). A heartbeat push is gate-governed and never
+	// bypassed.
+	Bypassed bool
 	// Detail is a short human-readable note (e.g. client count, decision reason).
 	Detail string
 	// Err is the underlying error text when delivery failed, or that of the
@@ -60,9 +64,9 @@ type PushResult struct {
 // String returns a concise summary for logs.
 func (p PushResult) String() string {
 	if p.Err != "" {
-		return fmt.Sprintf("pushed=%v route=%s detail=%q err=%q", p.Pushed, p.Route, p.Detail, p.Err)
+		return fmt.Sprintf("pushed=%v route=%s bypass=%v detail=%q err=%q", p.Pushed, p.Route, p.Bypassed, p.Detail, p.Err)
 	}
-	return fmt.Sprintf("pushed=%v route=%s detail=%q", p.Pushed, p.Route, p.Detail)
+	return fmt.Sprintf("pushed=%v route=%s bypass=%v detail=%q", p.Pushed, p.Route, p.Bypassed, p.Detail)
 }
 
 // ActiveClient delivers a proactive message to every currently active web/native
@@ -106,6 +110,9 @@ type PushRequest struct {
 	Message adapter.UnifiedMessage
 	// ChannelHint is the requested target channel, "" when she did not choose one.
 	ChannelHint string
+	// TriggerKind records what woke this pass. An event-driven push bypasses the
+	// PushGate (owner mandate: "该发就发"); a heartbeat stays gate-governed.
+	TriggerKind TriggerKind
 }
 
 // Pusher delivers a proactive message to ONE target channel. It is bounded by the
@@ -148,7 +155,12 @@ func (p *pusher) Push(ctx context.Context, req PushRequest) PushResult {
 		return PushResult{Pushed: false, Route: RouteNone, Err: err.Error()}
 	}
 	kind := classifyPush(req.Message.Content)
-	if p.gate != nil && !p.gate.Allow(ctx, kind) {
+	// A real event-driven push bypasses the PushGate: it should go out as-is ("该发就发"),
+	// independent of the heartbeat throttle (60min≤1 / cooldown / per-flavor window).
+	// Only the periodic heartbeat stays gate-governed, so the owner is never spammed
+	// by an empty reflection. Same-event dedup is applied upstream in think().
+	eventDriven := req.TriggerKind == TriggerEvent
+	if p.gate != nil && !eventDriven && !p.gate.Allow(ctx, kind) {
 		p.log.Warn("backthink push rate limited", "kind", kind.String())
 		return PushResult{Pushed: false, Route: RouteRateLimited, Detail: "proactive push rate limited"}
 	}
@@ -174,12 +186,18 @@ func (p *pusher) Push(ctx context.Context, req PushRequest) PushResult {
 			res = p.pushActive(ctx, msg)
 		}
 	}
-	// Only a real delivery advances the cooldown/per-kind windows, so an
-	// attempted-but-failed push does not suppress a later genuine one.
-	if res.Pushed && p.gate != nil {
+	// Only a real delivery advances the cooldown/per-kind windows (and only for a
+	// gate-governed push), so an attempted-but-failed push does not suppress a later
+	// genuine one, and an event push never contributes to the heartbeat throttle.
+	if res.Pushed && p.gate != nil && !eventDriven {
 		p.gate.RecordPush(kind)
 	}
-	return annotateHint(res, req.ChannelHint)
+	res = annotateHint(res, req.ChannelHint)
+	if eventDriven {
+		res.Bypassed = true
+		res = annotateBypass(res)
+	}
+	return res
 }
 
 // pushActive delivers only to the active web/native client.
@@ -246,6 +264,17 @@ func annotateHint(res PushResult, hint string) PushResult {
 	return res
 }
 
+// annotateBypass tags an event-driven push result so the record/panel shows it
+// skipped the PushGate, distinct from a heartbeat push that was rate-limited.
+func annotateBypass(res PushResult) PushResult {
+	if res.Detail == "" {
+		res.Detail = "event_bypass"
+	} else {
+		res.Detail = res.Detail + ", event_bypass"
+	}
+	return res
+}
+
 // rateGate is the production PushGate: a sliding-window counter over
 // session.RateLimiter (design/11 §6 anti-spam rule) combined with a post-push
 // cooldown and a per-flavor (问候/提醒/分享/关心) window so the owner is never