feat: arcim migration wizard UX, import fixes, Sentry setup (#22)

* feat: import system improvements, INK2 fix, and Swedish text corrections

- SIE parser: Windows-1252 and CP437 encoding detection and decoding
- Bank file parser: add Nordea Business (Företag) CSV format
- Bank file parser: improve format detection for SEB, Länsförsäkringar, generic CSV
- INK2 engine: calculate årets resultat (7222) from income statement for open fiscal years
- Dashboard: parallel Supabase queries, simplified dashboard page
- Fix Swedish characters (å, ä, ö) in BAS data descriptions, validation messages, AI consent disclosures
- Import wizard UI improvements across all steps
- Migration: add 'bas_range' match type to sie_account_mappings constraint
- Extensive new tests for SIE parser encoding and bank file parser

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

* feat: arcim migration wizard UX fixes, Sentry setup, and extension scaffolding

Arcim migration wizard improvements:
- Progress bar now excludes non-interactive steps (migrating/result)
- Fix OAuth text to match target="_blank" behavior (new tab, not redirect)
- Display month names instead of "Månad X" in preview
- Fix Swedish typo "förifylla" in no-company-info message
- Replace native checkboxes with shadcn Switch in options step
- Add ConfirmationDialog before starting migration
- Show progress percentage during migration
- Add "Nästa steg" guidance and navigation links in result step
- Add "Försök igen" button in error state (returns to options)
- Add Bokio company ID help text (GUID from URL)
- Add Fortnox integration add-on hint on connection failure

Also includes: SIE import system improvements, INK2 fixes, Swedish text
corrections, Sentry error tracking setup, and arcim-migration extension
scaffolding.

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

* fix: address PR review feedback

- Fix OAuth error recovery blank page (restore provider from URL params)
- Pass real userId to MigrationWizard instead of empty string
- Remove ~50 debug console.log statements from sie-import.ts
- Fix comment referencing account 3740 → 3741

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

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

components/import/SIEPreviewStep.tsx

@@ -13,6 +13,7 @@ import {
   XCircle,
   ArrowRight,
   BarChart3,
+  Info,
 } from 'lucide-react'
 import type { ImportPreview, ParseIssue } from '@/lib/import/types'
 
@@ -226,6 +227,16 @@ export default function SIEPreviewStep({
         </CardContent>
       </Card>
 
+      {/* Excluded system accounts info */}
+      {preview.excludedSystemAccounts.length > 0 && (
+        <div className="flex items-start gap-2 rounded-lg border bg-muted/50 px-4 py-3 text-sm text-muted-foreground">
+          <Info className="h-4 w-4 mt-0.5 flex-shrink-0" />
+          <span>
+            {preview.excludedSystemAccounts.length} internt systemkonto från källsystemet exkluderades ({preview.excludedSystemAccounts.map((a) => a.number).join(', ')}) — inte bokföringskonton
+          </span>
+        </div>
+      )}
+
       {/* Create missing accounts */}
       {missingAccounts.length > 0 && (
         <Card className="border-primary/50">