[skyzhao1223]

Fixes a nil pointer dereference in the chatflow success path.

Problem

In application/workflow/chatflow.go, the WorkflowSuccess branch dereferences intermediateMessage.Content when suggest mode is enabled:

if info.suggestReplyInfo != nil && ... && info.suggestReplyInfo.GetSuggestReplyMode() != ...Disable {
    sInfo := &vo.SuggestInfo{
        AnswerInput: schema.AssistantMessage(intermediateMessage.Content, nil),
        ...

But intermediateMessage starts as nil and is only assigned when a DataMessage is received (the needRegeneratedMessage path, around line 1106). A workflow that completes without emitting any DataMessage (e.g. an end-only workflow, or one whose outputs are all StateMessages) reaches this line with intermediateMessage == nil → nil pointer dereference panic.

Every other access site in the same function (:818, :931, :953) already guards with intermediateMessage != nil; this one was missed.

Fix

Add && intermediateMessage != nil to the suggest-mode condition. When there is no intermediate message there is nothing to base suggestions on, so suggest generation is skipped (safe degradation) instead of panicking.

go build ./application/workflow/
go test ./application/workflow/