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>

lib/extensions/__tests__/invoice-inbox-utils.test.ts

@@ -65,6 +65,7 @@ describe('formatExtractionSummary', () => {
       supplierName: '',
       total: 0,
       lineCount: 0,
+      currency: 'SEK',
     })
   })
 
@@ -73,6 +74,7 @@ describe('formatExtractionSummary', () => {
       supplierName: '',
       total: 0,
       lineCount: 0,
+      currency: 'SEK',
     })
   })
 
@@ -106,6 +108,7 @@ describe('formatExtractionSummary', () => {
       supplierName: 'Acme AB',
       total: 250,
       lineCount: 2,
+      currency: 'SEK',
     })
   })
 
@@ -123,6 +126,7 @@ describe('formatExtractionSummary', () => {
       supplierName: '',
       total: 0,
       lineCount: 0,
+      currency: 'SEK',
     })
   })
 })