Apply the /simplify cleanup to the C6 commit (identity maps, dead branches,
relationshipId reuse, native base64url, rowCount fix, canManageCampaignUsers
reuse) and register the unimplemented debits as roadmap item C8 with its plan.
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.
Next.js requires every export from a 'use server' module to be async; move the import type guard into a shared util and mark createSupporterRecord async. Also mark C2 as merged in the roadmap/docs.
