[FEATURE] Allow labelling of outputs for conditions etc

[phasmax]

Describe the feature you'd like
In the previous AgentFlow V1, outputs were labelled, so you could clearly see where the connections were going. Now there's no label, so you have to guess, or go back into the node and check it's index (which also doesn't align (0-based, vs 1-based). Can we please put a label field on the outputs, and have them show (even if it's on hover for now) on the output stubs.

[HenryHengZJ]

Yeah we have plan to allow label editing