Refactor to generic ERP base

Remove influencer-specific features (campaigns, TikTok, gifts, shadow ledger,
contracts, briefings) and consolidate into a clean ERP foundation with core
bookkeeping, invoicing, receipts, tax reporting, and calendar functionality.
Reorganize database migrations into a clean numbered sequence.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

lib/receipts/receipt-categorizer.ts

@@ -35,8 +35,6 @@ const BAS_ACCOUNT_MAPPING: Record<TransactionCategory, string> = {
   // Non-expense categories (for completeness)
   income_services: '3001',
   income_products: '3001',
-  income_sponsorship: '3900',
-  income_affiliate: '3900',
   income_other: '3900',
   private: '2013',
   uncategorized: '6991',
@@ -281,8 +279,6 @@ export const CATEGORY_LABELS: Record<TransactionCategory, string> = {
   expense_other: 'Övrigt',
   income_services: 'Tjänsteintäkt',
   income_products: 'Varuintäkt',
-  income_sponsorship: 'Sponsoring',
-  income_affiliate: 'Affiliate',
   income_other: 'Övrig intäkt',
   private: 'Privat',
   uncategorized: 'Ej kategoriserad',