Explicitly rehydrate a local Session Resource for Provider inspection.
resource_view is the model-facing side of ADR 0021's Resource View concept:
resources replay as lightweight descriptors, but a model may call this tool
when it needs exact visual evidence. The first supported projection is image
rehydration: the tool verifies that the resource descriptor exists in the
Session Log and that the local image payload still exists; the Provider then
projects the image on the next model call.