MoltenHub setup hardening and website registry updates.

Hardened hub startup/runtime behavior with wake-up ping retries, concurrent multi-repo cloning, registry-driven setup-location resolution, and configurable log-level defaults.

Resolved execution reliability edge cases across false failure detection, clone-owner typo handling, stuck agent-stage progression, unsaved hub-setup state, and queue-warning dedupe behavior.

Refined Hub UI workflows by syncing emoji-picker behavior with user-portal, restoring resource metric labels, and exposing full prompt text in fullscreen task view.

Published the Hub registry snapshot in `public/hubs.json` for the website's Hub directory data feed.

Expanded `/code` page guidance and visuals by adding prompt instructions plus refreshed task/library screenshot assets.