feat: implement automatic format inference service with candidate generation and prediction model

- Add formatCandidateRules.ts to define rules for generating format candidates based on file features.
- Introduce formatPredictionModel.ts to predict the most likely target format based on user behavior and file features.
- Create inferenceService.ts to integrate all inference modules and provide a unified inference API.
- Develop inference.tsx as an API endpoint for frontend calls to predict formats and engines based on file extensions.
- Implement logging for conversion events and dismissals, along with user profile retrieval.
- Ensure warmup management for engine predictions and provide status checks.

knip.json

@@ -5,7 +5,7 @@
   "tailwind": {
     "entry": ["src/main.css"]
   },
-  "ignore": ["src/i18n/**", "tests/e2e/helpers.ts"],
+  "ignore": ["src/i18n/**", "tests/e2e/helpers.ts", "src/inference/**"],
   "ignoreDependencies": [],
   "ignoreExportsUsedInFile": true
 }