refactor: consolidate AI analyzers into shared lib/ai module and add journal entry reversal columns

Extract shared vision/document analysis logic into lib/ai (vision-client, document-analyzer,
image preprocessing, validation helpers), simplifying invoice-analyzer, receipt-analyzer, and
document classifier. Add migration 046 for journal entry reversal/correction link columns
(reversed_by_id, reverses_id, correction_of_id) required by storno service. Update extension
components and shared UI.

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

components/extensions/shared/DateRangeFilter.tsx

@@ -43,9 +43,9 @@ export default function DateRangeFilter({ onRangeChange, className }: DateRangeF
   }
 
   const periods: { key: Period; label: string }[] = [
-    { key: 'month', label: 'M\u00e5nad' },
+    { key: 'month', label: 'Månad' },
     { key: 'quarter', label: 'Kvartal' },
-    { key: 'year', label: '\u00c5r' },
+    { key: 'year', label: 'År' },
   ]
 
   return (

components/extensions/shared/EmptyExtensionState.tsx

@@ -7,8 +7,8 @@ interface EmptyExtensionStateProps {
 }
 
 export default function EmptyExtensionState({
-  title = 'Ingen data \u00e4nnu',
-  description = 'Data kommer att visas h\u00e4r n\u00e4r det finns tillg\u00e4ngligt.',
+  title = 'Ingen data ännu',
+  description = 'Data kommer att visas här när det finns tillgängligt.',
   icon,
 }: EmptyExtensionStateProps) {
   return (