feat: open-source under AGPL-3.0, redesign UI to grayscale palette, add uncategorize API, fix VAT account names

Add LICENSE (AGPL-3.0-or-later), CONTRIBUTING.md, SECURITY.md, DCO, and NOTICE files.
Rewrite README for open-source audience with self-hosting instructions.
Redesign color palette to grayscale chrome theme across all components.
Add transaction uncategorize API route with tests.
Fix VAT account name mismatches in migration 052.
Improve import page with SIE file support and loading skeleton.

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

components/reports/BankReconciliationView.tsx

@@ -282,7 +282,7 @@ export function BankReconciliationView() {
             <div className="flex items-center justify-between">
               <CardTitle>Avstämning mot <AccountNumber number="1930" /></CardTitle>
               {status.is_reconciled ? (
-                <Badge className="bg-green-100 text-green-800">Avstämd</Badge>
+                <Badge className="bg-success/10 text-success">Avstämd</Badge>
               ) : (
                 <Badge variant="destructive">Ej avstämd</Badge>
               )}

components/reports/INK2DeclarationView.tsx

@@ -203,13 +203,13 @@ export function INK2DeclarationView({ periodId }: { periodId: string }) {
                 <tfoot>
                   <tr className="border-t font-medium">
                     <td className="py-2">Rörelseresultat</td>
-                    <td className={`py-2 text-right ${data.totals.operatingResult >= 0 ? 'text-green-600' : 'text-red-600'}`}>
+                    <td className={`py-2 text-right ${data.totals.operatingResult >= 0 ? 'text-success' : 'text-destructive'}`}>
                       {formatCurrency(data.totals.operatingResult)}
                     </td>
                   </tr>
                   <tr className="border-t-2 font-semibold">
                     <td className="py-2">Resultat efter finansiella poster</td>
-                    <td className={`py-2 text-right ${data.totals.resultAfterFinancial >= 0 ? 'text-green-600' : 'text-red-600'}`}>
+                    <td className={`py-2 text-right ${data.totals.resultAfterFinancial >= 0 ? 'text-success' : 'text-destructive'}`}>
                       {formatCurrency(data.totals.resultAfterFinancial)}
                     </td>
                   </tr>

components/reports/NEDeclarationView.tsx

@@ -211,7 +211,7 @@ export function NEDeclarationView({ periodId }: { periodId: string }) {
                 </div>
                 <span
                   className={`text-2xl font-bold ${
-                    data.rutor.R11 >= 0 ? 'text-green-600' : 'text-red-600'
+                    data.rutor.R11 >= 0 ? 'text-success' : 'text-destructive'
                   }`}
                 >
                   {formatCurrency(data.rutor.R11)}