feat: reverse charge VAT (ruta 20-32) + mobile UX improvements (#50)

* fix: include reversed entries in all reports (general ledger, trial balance, VAT, SIE, NE, INK2)

Reversed entries (storno) must appear alongside their original posted entries
in reports for a complete audit trail. Previously, filtering by status='posted'
excluded them, causing discrepancies when corrections had been made.

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

* feat: semi-manual invoice payment booking with editable journal lines

When marking an invoice as paid, users now see a dialog where they can:
- Choose which bank/cash account the payment goes to (1910, 1920, 1930, etc.)
- Review and edit the proposed journal entry lines before committing
- The happy path remains fast — lines are pre-filled correctly

Implementation:
- Pure proposePaymentLines() function for line computation (accrual + cash)
- PaymentBookingDialog with AccountCombobox, balance validation, date picker
- API accepts optional custom lines, falls back to auto-generation without them
- 18 tests (8 unit + 10 API) all passing

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

* fix: address Greptile review — validation fallback, balance check, error handling

- P1: Return 400 on invalid body instead of silently falling back to
  auto-generated lines (split JSON parse from schema validation)
- P1: Add server-side balance check for custom lines before committing
  (debit must equal credit, totalDebit > 0)
- P2: Wrap PaymentBookingDialog init() in try/catch with toast on
  failure and auto-close instead of silent empty state
- Add 2 new tests: unbalanced lines → 400, invalid schema → 400

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

* fix: OAuth callback redirect for local dev and timeout resilience

- Pass redirectUri dynamically from NEXT_PUBLIC_APP_URL so OAuth
  callbacks work on localhost (not just production)
- Encode consentId/provider in OAuth state (base64url JSON) so the
  callback doesn't depend on session storage
- Add skipAuth flag to extension API routes for OAuth callbacks
  (external provider redirects have no user session cookie)
- Wrap AbortError in descriptive timeout messages in arcim-client
- Make preview endpoint resilient to partial failures (company info
  and SIE fetch are individually non-blocking)
- Simplify login page (remove unused magic link auth mode)

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

* fix: create journal entry before marking invoice as paid

Move journal entry creation before the invoice status update so that
if accounting fails, the invoice is not permanently marked paid without
a corresponding entry. Previously the error was silently swallowed.

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

* fix: update mark-paid tests for journal-first ordering

Reorder mock queue to match new flow (settings before update), update
failure test to expect 500 instead of silent success, add try-catch
with proper error response in route handler.

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

* feat: add reverse charge VAT (ruta 20-32) and improve mobile UX across dashboard

Add full reverse charge (omvänd skattskyldighet) support to the VAT declaration:
- Map accounts 2614/2624/2634 to ruta 30/31/32 for self-assessed output VAT
- Calculate purchase bases (ruta 20-24) from supplier invoices by supplier type
- Include ruta 30-32 in ruta 49 formula and totalOutputVat summary
- Display reverse charge section in reports UI and composition chart
- Add comprehensive test coverage for all reverse charge scenarios

Improve mobile UX across the app:
- Convert nav drawer to bottom sheet with drag handle and safe area padding
- Add mobile card layout for PaymentBookingDialog journal lines
- Replace settings tab pills with dropdown selector on mobile
- Make wizard step indicators responsive (collapsed on mobile)
- Ensure all dialog footers stack buttons full-width on mobile
- Add 44px minimum touch targets throughout
- Make onboarding buttons full-width on mobile

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

* fix: address Greptile review — indentation, query efficiency, tab dedup

- Fix misleading try-block indentation in mark-paid route
- Filter reversed entries at DB level (.eq('status', 'posted')) instead
  of fetching then discarding in memory
- Extract shared settingsTabs array so mobile Select and desktop
  TabsList stay in sync automatically

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

---------

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

components/extensions/general/ArcimMigrationWorkspace.tsx

@@ -7,6 +7,7 @@ import { Button } from '@/components/ui/button'
 import { Input } from '@/components/ui/input'
 import { Switch } from '@/components/ui/switch'
 import { useToast } from '@/components/ui/use-toast'
+import { cn } from '@/lib/utils'
 import { ConfirmationDialog } from '@/components/ui/confirmation-dialog'
 import Link from 'next/link'
 import {
@@ -1513,10 +1514,16 @@ export default function ArcimMigrationWorkspace(_props: WorkspaceComponentProps)
           <CardContent className="pt-6">
             <div className="space-y-2">
               <div className="flex justify-between text-sm">
+                <span className="sm:hidden text-primary font-medium">
+                  Steg {currentUserStepIndex + 1}/{userSteps.length}: {STEP_LABELS[step]}
+                </span>
                 {userSteps.map((s) => (
                   <span
                     key={s}
-                    className={userSteps.indexOf(s) <= currentUserStepIndex ? 'font-medium text-primary' : 'text-muted-foreground'}
+                    className={cn(
+                      'hidden sm:inline',
+                      userSteps.indexOf(s) <= currentUserStepIndex ? 'font-medium text-primary' : 'text-muted-foreground'
+                    )}
                   >
                     {STEP_LABELS[s]}
                   </span>