name no consumer of this node

A source that documents itself through a specific downstream node depends on
that node to be understood, and that node already depends on this one for
frames. The README pointed at one by name and the CI workflow still carried a
comment about the dataflow that wired it, which no longer exists.

The output is documented by its type instead: wire `image` into anything that
takes std/media/v1/Image. PREVIEW covers seeing the frames without naming
anyone. Generic words like "a viewer" or "a consumer" stay, since they describe
a role rather than a repository.

.gitea/workflows/validate.yml

@@ -75,8 +75,6 @@ jobs:
       - name: Validate the dataflow
         run: dora validate dataflow.yml
 
-      # dataflow_view.yml is deliberately not run: it fetches dora-image-view
-      # over the network and needs a tag to exist there.
       # CAPTURE_FRAMES bounds the run so it ends on its own; CI=true is already
       # set by the runner, which makes a failed capture publish a placeholder
       # frame rather than raising on a machine with no camera.