fix: reminder platform 改用 AdapterName（唯一标识符），不再硬编码 obv11

- ProcessParams/SynthesizeParams 新增 AdapterName
- main.go 传递 req.Source.AdapterName
- reminder_create 自动注入使用 adapter 名而非平台类型

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

backend/ai-core/cmd/main.go

@@ -1086,6 +1086,7 @@ func handleChat(
 		ChannelType: req.Source.ChannelType,
 		ChannelID:   req.Source.ChannelID,
 		BotUID:      req.Source.BotUID,
+		AdapterName: req.Source.AdapterName,
 	})
 	if err != nil {
 		fallback := getFallbackMessage()

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

@@ -154,6 +154,7 @@ type ProcessParams struct {
 	ChannelType string // direct / group
 	ChannelID   string // platform channel ID (group ID or private OBv11 number)
 	BotUID      string // bot's own platform UID (e.g., OBv11 account)
+	AdapterName string // adapter config name for routing
 }
 
 // ProcessResult 处理结果
@@ -430,6 +431,7 @@ func (o *Orchestrator) ProcessInput(
 			Mode:          params.Mode,
 			ChannelType:   params.ChannelType,
 			ChannelID:    params.ChannelID,
+			AdapterName:  params.AdapterName,
 		}
 		if prevEnrichment != nil {
 			synthParams.MemorySummary = prevEnrichment.MemorySummary

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

@@ -54,6 +54,7 @@ type SynthesizeParams struct {
 	Mode               string                      // text / voice_assistant
 	ChannelType        string                      // direct / group
 	ChannelID          string                      // platform channel ID
+	AdapterName        string                      // adapter config name
 }
 
 // Synthesize 综合所有子会话结果，流式生成最终回复。
@@ -97,7 +98,7 @@ func (s *Synthesizer) Synthesize(ctx context.Context, params SynthesizeParams, e
 			// 自动注入当前会话的平台信息（reminder_create 需要知道来源）
 			if tc.Name == "reminder_create" && params.ChannelType != "" {
 				if _, ok := args["platform"]; !ok || args["platform"] == "" {
-					args["platform"] = "obv11"
+					args["platform"] = params.AdapterName
 				}
 				if _, ok := args["channel_type"]; !ok || args["channel_type"] == "" {
 					args["channel_type"] = params.ChannelType