Multi-organisation users

[tudddorrr]

Multi-organisation memberships

• Users can now belong to multiple organisations through a new OrganisationMember entity, backfilled from existing users by migration.
• Invites are scoped per organisation, so the same email can be invited by several organisations instead of being blocked after the first.
• New endpoints let users list their memberships and switch their active organisation.

Organisation administration

• Member type changes and removals now operate on memberships rather than assuming a single home organisation.
• Removing a member reassigns them to another organisation they belong to, or creates a fresh one for them when none remain.
• Removing a member also clears invites sent to that email.

Identity and session changes

• User responses and tokens now carry membership data so clients can render an organisation switcher.
• Pinned-group cache keys include the organisation to avoid collisions across organisations.