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>

lib/api/schemas.ts

@@ -387,6 +387,16 @@ export const UpdateSettingsSchema = z.object({
   website: z.string().optional().or(z.literal('')),
   pays_salaries: z.boolean().optional(),
   sector_slug: z.string().nullable().optional(),
+  // Bookkeeping lock
+  bookkeeping_locked_through: z.string().regex(/^\d{4}-\d{2}-\d{2}$/, 'Ogiltigt datumformat (YYYY-MM-DD)').nullable().optional(),
+  auto_lock_period_days: z.number().int().positive().nullable().optional(),
+  // Invoice PDF settings
+  ore_rounding: z.boolean().optional(),
+  invoice_show_ocr: z.boolean().optional(),
+  invoice_show_bankgiro: z.boolean().optional(),
+  invoice_show_plusgiro: z.boolean().optional(),
+  invoice_late_fee_text: z.string().nullable().optional(),
+  invoice_credit_terms_text: z.string().nullable().optional(),
 }).refine(
   (data) => {
     // BFL 3 kap.: Enskild firma must have fiscal year starting January
@@ -573,3 +583,20 @@ export const PendingOperationsQuerySchema = z.object({
   limit: z.coerce.number().int().min(1).max(100).default(50),
   offset: z.coerce.number().int().nonnegative().default(0),
 })
+
+// ============================================================
+// Voucher gap schemas
+// ============================================================
+
+export const VoucherGapQuerySchema = z.object({
+  fiscal_period_id: uuid,
+  voucher_series: z.string().optional(),
+})
+
+export const SaveGapExplanationSchema = z.object({
+  fiscal_period_id: uuid,
+  voucher_series: z.string().default('A'),
+  gap_start: z.number().int().positive(),
+  gap_end: z.number().int().positive(),
+  explanation: z.string().min(1).max(500),
+})