feat: import system improvements, INK2 fix, and Swedish text corrections (#10)

- 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>

components/import/AccountMappingStep.tsx

@@ -204,7 +204,7 @@ export default function AccountMappingStep({
           </div>
 
           {/* Mapping table */}
-          <div className="border rounded-lg overflow-hidden">
+          <div className="border rounded-lg overflow-x-auto">
             <Table>
               <TableHeader>
                 <TableRow>
@@ -317,11 +317,11 @@ export default function AccountMappingStep({
       </Card>
 
       {/* Actions */}
-      <div className="flex justify-between">
-        <Button variant="outline" onClick={onBack}>
+      <div className="flex flex-col-reverse gap-3 sm:flex-row sm:justify-between">
+        <Button variant="outline" className="min-h-11" onClick={onBack}>
           Tillbaka
         </Button>
-        <Button onClick={onContinue} disabled={!canContinue}>
+        <Button className="min-h-11" onClick={onContinue} disabled={!canContinue}>
           {canContinue ? 'Fortsätt till granskning' : `${stats.unmapped} konton saknar mappning`}
           <ArrowRight className="ml-2 h-4 w-4" />
         </Button>