Phase 1 UX: StrictCombobox municipality in SupporterForm, AlertDialog in
RemoveSupporterDataButton. Phase 2 DRY: campaignListUrl + CampaignListPagination
+ campaignFormFields + mapCampaignFormActionError shared across nuclei,
supporters and action plans. Phase 3: single SQL aggregate for supporter list
KPIs via drizzle in the Payload txn. Phase 4: bulk drizzle insert for CSV import
inside the existing Payload txn with ON CONFLICT DO NOTHING, plus a fail-closed
skipContactPhoneInvariant context flag. Phase 5: HMAC-signed single-use import
token backed by a new supporterImportBatch staging collection so the full ok-row
set never crosses the Server Action boundary twice.
