feat: 异步工具结果主动推送 — 通用回调机制

- Synthesizer 新增 resultPusher 回调字段
- executeAsyncAndStore 完成后自动推送结果
- Orchestrator.SetToolResultPusher 透传
- 回调通用设计，不绑定特定工具

Co-Authored-By: Claude <noreply@anthropic.com>

backend/ai-core/internal/orchestrator/orchestrator.go

@@ -82,6 +82,11 @@ func (o *Orchestrator) SetToolRegistry(tr *plgManager.ToolRegistry) {
 	o.synthesizer.toolRegistry = tr
 }
 
+// SetToolResultPusher sets the callback for proactive tool result delivery.
+func (o *Orchestrator) SetToolResultPusher(pusher func(sessionID, userID, toolName, result string)) {
+	o.synthesizer.SetResultPusher(pusher)
+}
+
 // SetVisionProvider sets the vision model provider for image preprocessing.
 func (o *Orchestrator) SetVisionProvider(vp llm.LLMProvider) {
 	o.visionProvider = vp

backend/ai-core/internal/orchestrator/synthesizer.go

@@ -19,6 +19,7 @@ import (
 type Synthesizer struct {
 	llmAdapter   *llm.Adapter
 	toolRegistry *plgManager.ToolRegistry
+	resultPusher func(sessionID, userID, toolName, result string)
 }
 
 // NewSynthesizer 创建综合器
@@ -29,6 +30,11 @@ func NewSynthesizer(llmAdapter *llm.Adapter, toolRegistry *plgManager.ToolRegist
 	}
 }
 
+// SetResultPusher sets the callback for proactive tool result delivery.
+func (s *Synthesizer) SetResultPusher(pusher func(sessionID, userID, toolName, result string)) {
+	s.resultPusher = pusher
+}
+
 // SynthesizeParams 综合参数
 type SynthesizeParams struct {
 	UserID             string
@@ -172,6 +178,10 @@ func (s *Synthesizer) executeAsyncAndStore(tc model.ToolCall, args map[string]in
 			Success:    result != nil && result.Success,
 		})
 	}
+	// 主动推送工具结果
+	if s.resultPusher != nil && result != nil && result.Success {
+		s.resultPusher(sessionID, "", tc.Name, string(resultJSON))
+	}
 }
 
 // buildSynthesizeMessages 构建综合用的 LLM 消息列表