Groundwork for connectors on shared artifacts

What

• The share-status record for artifacts (shareable outputs Claude Code creates) gains endpointConnectors, connectorsIssuedAt and lastConnectorsReadToolUseId. The copy step passes them through when present. No code in this build sets them.
• When the account changes, these three fields are removed from each artifact's stored share status (bySlug). Before, they were kept.
• The check of saved state now also looks at these three fields.
• The state that tracks consent questions gains inheritedTypeGrantLatch, askClassRequestShown and askConnectorsShown.

Why

This is groundwork for connectors attached to artifacts, with nothing using it yet. One effect is already in place: connector details stored under one account do not carry over when you switch to another.