feat: merge user-description-match into ai-categorization with AI-powered description analysis

Consolidate the standalone user-description-match extension into ai-categorization,
adding an AI description analyzer that provides account/VAT suggestions alongside
template matching. The describe transaction dialog now shows AI suggestions with
confidence scores and supports both template-based and AI-based booking.

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

extensions.md

@@ -64,7 +64,6 @@ extensions/
     invoice-inbox/
     calendar/
     email/
-    user-description-match/
   restaurant/                 ← Restaurant sector extensions
     food-cost/
     earnings-per-liter/
@@ -334,9 +333,6 @@ extensions/                           ← Extension source code (opt-in via conf
     calendar/
       manifest.json
       index.ts
-    user-description-match/
-      manifest.json
-      index.ts
   restaurant/                         ← Restaurant sector
     food-cost/
       manifest.json