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>

app/api/reports/sie-export/route.ts

@@ -33,7 +33,7 @@ export async function GET(request: Request) {
       fiscal_period_id: periodId,
       company_name: company.company_name || 'Unknown',
       org_number: company.org_number,
-      program_name: 'InfluencerBiz',
+      program_name: 'ERPBase',
     })
 
     // Return as downloadable file