Blocking text gate: pauses, shows incoming text in an editable box, Pass
emits the edited text. Optional any-type signal input + signal passthrough
output for ordering. Reuses gate_bus via an additive string payload channel
with a should_cancel hook so the Pass-only gate still honors global Cancel
(processing_interrupted). TDD plan; comfy imports stay lazy for testability.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
