feat(flyer-import): integrate AI-based flyer parsing with image support

- Add support for PNG, JPEG, and WebP image formats in flyer import
- Replace external importer service with internal AI-based parsing pipeline
- Add new services: TextExtractorService, AiFlyerParserService, FlyerNormalizerService
- Integrate Mistral AI, pdf-parse, and tesseract.js dependencies
- Add quality confidence indicators and warning panels in Flutter UI
- Update package.json with new dependencies and transform ignore patterns
- Add documentation for flyer importer system
- Add Kilo AI planning file for Happy Island project

BREAKING CHANGE: Flyer import now uses internal AI parsing instead of external importer service

kilo.json

@@ -1,5 +1,3 @@
 {
-  "env": {
-    "MISTRAL_API_KEY": "process.env.MISTRAL_API_KEY"
-  }
-}
+  "$schema": "https://app.kilo.ai/config.json"
+}