Migrates Enterprise account_followup per-partner state to Fusion fields:
- res.partner.followup_status -> fusion_followup_status (action_due/no_action)
- res.partner.payment_next_action_date -> fusion_followup_paused_until
(when future-dated; sets status to 'paused')
- res.partner.followup_line_id -> fusion_followup_last_level_id
(resolved by name match against migrated levels)
Wired into fusion.migration.wizard.action_run_migration after the
existing _followup_bootstrap_step. Idempotent: skips partners whose
Fusion state is already non-default. Defensive against missing
Enterprise fields (each field probed individually before use).
Closes the per-partner state migration gap that was blocking
Enterprise account_followup uninstall.
Made-with: Cursor
679dbaa979