feat: agent slash menu backend (#37268)

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>

api/openapi/markdown/console-swagger.md

@@ -11808,6 +11808,7 @@ Get banner list
 | agent | [AgentComposerAgentResponse](#agentcomposeragentresponse) |  | Yes |
 | agent_soul | [AgentSoulConfig](#agentsoulconfig) |  | Yes |
 | save_options | [ [ComposerSaveStrategy](#composersavestrategy) ] |  | Yes |
+| validation | [ComposerValidationFindingsResponse](#composervalidationfindingsresponse) |  | No |
 | variant | string |  | Yes |
 
 #### AgentAppFeaturesPayload
@@ -11903,6 +11904,7 @@ Risk marker for CLI tool bootstrap commands.
 | allowed_node_job_candidates | [AgentComposerNodeJobCandidatesResponse](#agentcomposernodejobcandidatesresponse) |  | No |
 | allowed_soul_candidates | [AgentComposerSoulCandidatesResponse](#agentcomposersoulcandidatesresponse) |  | No |
 | capabilities | [ComposerCandidateCapabilities](#composercandidatecapabilities) |  | No |
+| truncated | boolean |  | No |
 | variant | [ComposerVariant](#composervariant) |  | Yes |
 
 #### AgentComposerDifyToolCandidateResponse
@@ -11916,6 +11918,22 @@ Risk marker for CLI tool bootstrap commands.
 | provider | string |  | No |
 | provider_id | string |  | No |
 
+#### AgentComposerFileCandidateResponse
+
+| Name | Type | Description | Required |
+| ---- | ---- | ----------- | -------- |
+| file_id | string |  | No |
+| id | string |  | No |
+| kind | string |  | No |
+| name | string |  | No |
+| reference | string |  | No |
+| remote_url | string |  | No |
+| tenant_id | string |  | No |
+| transfer_method | string |  | No |
+| type | string |  | No |
+| upload_file_id | string |  | No |
+| url | string |  | No |
+
 #### AgentComposerImpactBindingResponse
 
 | Name | Type | Description | Required |
@@ -11940,6 +11958,17 @@ Risk marker for CLI tool bootstrap commands.
 | human_contacts | [ [AgentHumanContactConfig](#agenthumancontactconfig) ] |  | No |
 | previous_node_outputs | [ [WorkflowPreviousNodeOutputRef](#workflowpreviousnodeoutputref) ] |  | No |
 
+#### AgentComposerSkillCandidateResponse
+
+| Name | Type | Description | Required |
+| ---- | ---- | ----------- | -------- |
+| description | string |  | No |
+| file_id | string |  | No |
+| id | string |  | No |
+| kind | string |  | No |
+| name | string |  | No |
+| path | string |  | No |
+
 #### AgentComposerSoulCandidatesResponse
 
 | Name | Type | Description | Required |
@@ -11948,7 +11977,7 @@ Risk marker for CLI tool bootstrap commands.
 | dify_tools | [ [AgentComposerDifyToolCandidateResponse](#agentcomposerdifytoolcandidateresponse) ] |  | No |
 | human_contacts | [ [AgentHumanContactConfig](#agenthumancontactconfig) ] |  | No |
 | knowledge_datasets | [ [AgentKnowledgeDatasetConfig](#agentknowledgedatasetconfig) ] |  | No |
-| skills_files | [ [AgentSkillRefConfig](#agentskillrefconfig) ] |  | No |
+| skills_files | [  ] |  | No |
 
 #### AgentComposerSoulLockResponse
 
@@ -11963,7 +11992,9 @@ Risk marker for CLI tool bootstrap commands.
 | Name | Type | Description | Required |
 | ---- | ---- | ----------- | -------- |
 | errors | [ string ] |  | No |
+| knowledge_retrieval_placeholder | [ [ComposerKnowledgePlaceholderResponse](#composerknowledgeplaceholderresponse) ] |  | No |
 | result | string |  | Yes |
+| warnings | [ [ComposerValidationWarningResponse](#composervalidationwarningresponse) ] |  | No |
 
 #### AgentConfigRevisionOperation
 
@@ -13286,6 +13317,13 @@ Button styles for user actions.
 | ---- | ---- | ----------- | -------- |
 | human_roster_available | boolean |  | No |
 
+#### ComposerKnowledgePlaceholderResponse
+
+| Name | Type | Description | Required |
+| ---- | ---- | ----------- | -------- |
+| id | string |  | Yes |
+| placeholder_name | string |  | Yes |
+
 #### ComposerSavePayload
 
 | Name | Type | Description | Required |
@@ -13314,6 +13352,23 @@ Button styles for user actions.
 | locked | boolean |  | No |
 | unlocked_from_version_id | string |  | No |
 
+#### ComposerValidationFindingsResponse
+
+| Name | Type | Description | Required |
+| ---- | ---- | ----------- | -------- |
+| knowledge_retrieval_placeholder | [ [ComposerKnowledgePlaceholderResponse](#composerknowledgeplaceholderresponse) ] |  | No |
+| warnings | [ [ComposerValidationWarningResponse](#composervalidationwarningresponse) ] |  | No |
+
+#### ComposerValidationWarningResponse
+
+| Name | Type | Description | Required |
+| ---- | ---- | ----------- | -------- |
+| code | string |  | Yes |
+| id | string |  | No |
+| kind | string |  | No |
+| message | string |  | No |
+| surface | string |  | No |
+
 #### ComposerVariant
 
 | Name | Type | Description | Required |
@@ -17571,6 +17626,7 @@ How a workflow node is bound to an Agent.
 | node_job | [WorkflowNodeJobConfig](#workflownodejobconfig) |  | Yes |
 | save_options | [ [ComposerSaveStrategy](#composersavestrategy) ] |  | Yes |
 | soul_lock | [AgentComposerSoulLockResponse](#agentcomposersoullockresponse) |  | Yes |
+| validation | [ComposerValidationFindingsResponse](#composervalidationfindingsresponse) |  | No |
 | variant | string |  | Yes |
 | workflow_id | string |  | No |