feat: harden support, localize knowledge and add operator availability [skip ci]

Source-only publication of reviewed commit 64e96a7f423673dc29ad56485be9fc79bce8af1c.

Passed in isolation: focused frontend/backend tests, race checks, TypeScript typecheck, lint, Go compilation, Flowgram build, and deterministic SDK build/tests.

Not accepted as a production release: Next.js export/native assembly remains blocked by environment memory limits; browser interaction and MySQL staging acceptance remain unverified. No production server, database/schema, runtime configuration, deployment, release tag, or workflow execution was performed.

Expected source tree: 0a4a7528e9.

internal/services/knowledge_base_service.go

@@ -1,3 +1,4 @@
+// Modified in the independent AgentDesk fork: localized knowledge workflows and safe display errors.
 package services
 
 import (
@@ -136,9 +137,9 @@ func (s *knowledgeBaseService) DeleteKnowledgeBase(id int64) error {
 	referencingWorkflows := s.findWorkflowReferencesByKnowledgeBaseID(id)
 	if len(referencingWorkflows) > 0 {
 		if len(referencingWorkflows) == 1 {
-			return errorsx.Forbidden(fmt.Sprintf("知识库正在被流程「%s」使用，请先从知识检索节点中移除", referencingWorkflows[0]))
+			return errorsx.ForbiddenI18n("error.knowledge.workflowReference", referencingWorkflows[0])
 		}
-		return errorsx.Forbidden(fmt.Sprintf("知识库正在被 %d 个流程使用，请先从知识检索节点中移除", len(referencingWorkflows)))
+		return errorsx.ForbiddenI18n("error.knowledge.workflowReferences", len(referencingWorkflows))
 	}
 
 	if err := sqls.WithTransaction(func(ctx *sqls.TxContext) error {