Implement an option to delete a user and transfer their existing bookings to a new host

Description:
Implement an option to delete a user and transfer their existing bookings to a new host.

Current Workflow:

• Users cannot be deleted, only marked inactive. Existing bookings cannot be transferred in bulk, requiring manual updates one by one.

Proposed Workflow:

• Provide a delete‑and‑transfer workflow allowing admins to select a replacement host. Upon deletion, all existing and future bookings are automatically reassigned to the chosen user.

Business Reason:
Streamlines user offboarding, reduces manual admin effort, preserves booking continuity, and prevents orphaned bookings.