feat: remove AI extensions, restructure settings, and add atomic voucher commits (#157)

Remove AI-dependent extensions (ai-chat, ai-categorization, receipt-ocr,
invoice-inbox) and their infrastructure (lib/ai/*, ai-consent, LangChain/
Anthropic/OpenAI deps) to simplify core and reduce bundle size.

Restructure monolithic settings page into dedicated sub-pages (company,
bookkeeping, invoicing, tax, banking, api, account, team, templates) with
shared layout and sidebar navigation.

Add atomic commit_journal_entry RPC so voucher number increment and status
update happen in a single transaction — prevents burned numbers on constraint
failures. Add continuity check report and voucher gap explanation tracking.

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

app/api/extensions/enable-banking/sync/cron/route.ts

@@ -291,7 +291,7 @@ async function sendConsentExpiryNotification(
     const emailData = {
       bankName: connection.bank_name as string,
       daysUntilExpiry: daysLeft,
-      renewalUrl: `${baseUrl}/settings?tab=banking`,
+      renewalUrl: `${baseUrl}/settings/banking`,
       companyName: companySettings?.company_name || 'gnubok',
       isExpired,
     }