feat: add fallback mode for AI agents and update knowledge base handling

- Introduced AIAgentFallbackMode with options for NoAnswer and SuggestRetry.
- Updated AI agent edit component to include fallback mode selection.
- Modified API types and payloads to accommodate fallback mode.
- Removed deprecated KnowledgeFallbackMode and related logic from knowledge base.
- Adjusted knowledge retrieval and response handling to utilize new fallback logic.
- Updated tests to reflect changes in fallback mode handling for AI agents.

internal/ai/runtime/executor/knowledge_guard.go

@@ -19,7 +19,7 @@ func buildKnowledgeGuardDecision(aiAgent models.AIAgent, retrieveResult *retriev
 	if retrieveResult == nil || len(retrieveResult.KnowledgeBaseIDs) == 0 {
 		return knowledgeGuardDecision{}
 	}
-	fallbackReply := resolveKnowledgeFallbackReply(aiAgent, retrieveResult.FallbackMode)
+	fallbackReply := resolveKnowledgeFallbackReply(aiAgent)
 	if len(retrieveResult.Hits) == 0 {
 		return knowledgeGuardDecision{FallbackReply: fallbackReply}
 	}
@@ -32,15 +32,13 @@ func buildKnowledgeGuardDecision(aiAgent models.AIAgent, retrieveResult *retriev
 	}
 }
 
-func resolveKnowledgeFallbackReply(aiAgent models.AIAgent, fallbackMode enums.KnowledgeFallbackMode) string {
+func resolveKnowledgeFallbackReply(aiAgent models.AIAgent) string {
 	if reply := strings.TrimSpace(aiAgent.FallbackMessage); reply != "" {
 		return reply
 	}
-	switch fallbackMode {
-	case enums.KnowledgeFallbackModeSuggestRetry:
+	switch aiAgent.FallbackMode {
+	case enums.AIAgentFallbackModeSuggestRetry:
 		return "当前知识库里没有找到足够明确的信息，你可以换个更具体的问法再试一次。"
-	case enums.KnowledgeFallbackModeTransferHuman:
-		return "当前知识库里没有找到足够明确的信息，建议转人工进一步处理。"
 	default:
 		return "当前知识库暂无明确信息。"
 	}

internal/ai/runtime/executor/knowledge_guard_test.go

@@ -12,9 +12,9 @@ import (
 
 func TestBuildKnowledgeGuardDecisionFallsBackWhenKnowledgeMisses(t *testing.T) {
 	agent := newKnowledgeGuardAgentFixture()
+	agent.FallbackMode = enums.AIAgentFallbackModeSuggestRetry
 	decision := buildKnowledgeGuardDecision(agent, &retrievers.KnowledgeRetrieveResult{
 		KnowledgeBaseIDs: []int64{1},
-		FallbackMode:     enums.KnowledgeFallbackModeSuggestRetry,
 	})
 
 	if decision.FallbackReply != "当前知识库里没有找到足够明确的信息，你可以换个更具体的问法再试一次。" {
@@ -30,7 +30,6 @@ func TestBuildKnowledgeGuardDecisionUsesAgentFallbackMessage(t *testing.T) {
 	agent.FallbackMessage = "请联系人工客服"
 	decision := buildKnowledgeGuardDecision(agent, &retrievers.KnowledgeRetrieveResult{
 		KnowledgeBaseIDs: []int64{1},
-		FallbackMode:     enums.KnowledgeFallbackModeNoAnswer,
 	})
 
 	if decision.FallbackReply != "请联系人工客服" {
@@ -45,8 +44,7 @@ func TestBuildKnowledgeGuardDecisionInjectsStrictInstructionOnHit(t *testing.T)
 		Hits: []rag.RetrieveResult{
 			{KnowledgeBaseID: 1, Score: 0.88},
 		},
-		AnswerMode:   enums.KnowledgeAnswerModeStrict,
-		FallbackMode: enums.KnowledgeFallbackModeNoAnswer,
+		AnswerMode: enums.KnowledgeAnswerModeStrict,
 	})
 
 	if decision.FallbackReply != "" {
@@ -65,5 +63,7 @@ func TestBuildKnowledgeGuardDecisionInjectsStrictInstructionOnHit(t *testing.T)
 }
 
 func newKnowledgeGuardAgentFixture() models.AIAgent {
-	return models.AIAgent{}
+	return models.AIAgent{
+		FallbackMode: enums.AIAgentFallbackModeNoAnswer,
+	}
 }

internal/ai/runtime/internal/impl/retrievers/knowledge_retriever.go

@@ -46,7 +46,6 @@ type KnowledgeRetrieveResult struct {
 	ContextText      string
 	TopScore         float64
 	AnswerMode       enums.KnowledgeAnswerMode
-	FallbackMode     enums.KnowledgeFallbackMode
 	Trace            *rag.RetrieveTrace
 	TraceItems       []callbacks.RetrieverTraceItem
 	TraceSummary     callbacks.RetrieverTraceSummary
@@ -127,7 +126,7 @@ func (r *KnowledgeRetriever) RetrieveContextByOptions(ctx context.Context, opts
 	ret.ContextResults = limitContextResults(ret.ContextResults, maxContextItems)
 	ret.ContextText = strings.TrimSpace(buildContextText(ret.ContextResults))
 	ret.TopScore = resolveTopScore(results)
-	ret.AnswerMode, ret.FallbackMode = resolveRuntimeAnswerSettings(knowledgeBaseIDs, results)
+	ret.AnswerMode = resolveRuntimeAnswerMode(knowledgeBaseIDs, results)
 	ret.TraceItems = buildRetrieverTraceItems(queryPreview, results, trace)
 	ret.TraceSummary = buildRetrieverTraceSummary(ret.Options, ret.Policies, ret.ContextResults, results, trace)
 	return ret, nil
@@ -188,34 +187,30 @@ func (r *KnowledgeRetriever) resolvePolicies(knowledgeBaseIDs []int64, opts Know
 	return ret
 }
 
-func resolveRuntimeAnswerSettings(knowledgeBaseIDs []int64, results []rag.RetrieveResult) (enums.KnowledgeAnswerMode, enums.KnowledgeFallbackMode) {
+func resolveRuntimeAnswerMode(knowledgeBaseIDs []int64, results []rag.RetrieveResult) enums.KnowledgeAnswerMode {
 	knowledgeBases := loadRuntimeKnowledgeBases(knowledgeBaseIDs)
 	if len(knowledgeBases) == 0 {
-		return enums.KnowledgeAnswerModeStrict, enums.KnowledgeFallbackModeNoAnswer
+		return enums.KnowledgeAnswerModeStrict
 	}
 	if len(results) > 0 {
 		if knowledgeBase, ok := knowledgeBases[results[0].KnowledgeBaseID]; ok {
-			return normalizeRuntimeAnswerSettings(knowledgeBase)
+			return normalizeRuntimeAnswerMode(knowledgeBase)
 		}
 	}
 	for _, knowledgeBaseID := range knowledgeBaseIDs {
 		if knowledgeBase, ok := knowledgeBases[knowledgeBaseID]; ok {
-			return normalizeRuntimeAnswerSettings(knowledgeBase)
+			return normalizeRuntimeAnswerMode(knowledgeBase)
 		}
 	}
-	return enums.KnowledgeAnswerModeStrict, enums.KnowledgeFallbackModeNoAnswer
+	return enums.KnowledgeAnswerModeStrict
 }
 
-func normalizeRuntimeAnswerSettings(knowledgeBase models.KnowledgeBase) (enums.KnowledgeAnswerMode, enums.KnowledgeFallbackMode) {
+func normalizeRuntimeAnswerMode(knowledgeBase models.KnowledgeBase) enums.KnowledgeAnswerMode {
 	answerMode := enums.KnowledgeAnswerMode(knowledgeBase.AnswerMode)
 	if answerMode == 0 {
 		answerMode = enums.KnowledgeAnswerModeStrict
 	}
-	fallbackMode := enums.KnowledgeFallbackMode(knowledgeBase.FallbackMode)
-	if fallbackMode == 0 {
-		fallbackMode = enums.KnowledgeFallbackModeNoAnswer
-	}
-	return answerMode, fallbackMode
+	return answerMode
 }
 
 func loadRuntimeKnowledgeBases(ids []int64) map[int64]models.KnowledgeBase {