After the widget cleanup (30e3aa9), the SamplerGridTester is nearly
empty — just one required input (configs_json), six optional sockets,
and a single output. New users won't know how to wire it.
Adds a small footnote (~44px tall) at the bottom of the node via a
non-serialized DOM widget:
"Connect the configs_json from the Builder node to this node, and
connect this node to the Dashboard node"
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
