fix(hub): offer only experiments whose settings Configure can read

Closes #15 (closed). Configure reads an experiment's settings from python -m <module> --manifest; none of the five hub experiments answers it at the ref the bench installs, so each installed and then failed.

• CatalogueEntry.publishes_manifest: an experiment counts only when its published check passed on plesty-sdk >= 0.5.0 (that SDK's Experiment Manifest gate fails any module without ExperimentCLI). Read from the registry's existing quality.tooling — no registry change.
• installable requires it, so the Marketplace hides such experiments; install_entry refuses one with a message an operator can act on.
• Devices unchanged. Hub > Load from… still runs any checkout.

Today this hides every hub experiment until plesty-pol-pl 0.1.0 is released with a fresh check (in progress) and the others move to ExperimentCLI.