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>

package.json

@@ -52,6 +52,7 @@
     "recharts": "^3.7.0",
     "resend": "^6.9.1",
     "server-only": "^0.0.1",
+    "sharp": "^0.34.5",
     "svix": "^1.85.0",
     "tailwind-merge": "^3.4.0",
     "web-push": "^3.6.7",
@@ -62,6 +63,7 @@
     "@types/node": "^20",
     "@types/react": "^19",
     "@types/react-dom": "^19",
+    "@types/sharp": "^0.31.1",
     "@types/web-push": "^3.6.4",
     "dotenv": "^17.2.3",
     "eslint": "^9",