fix: update bindings for annotation extraction, WASM MIME exports, PaddleOCR validation (#403)

- Add assert_annotations helpers to all e2e generators (Go, Java, PHP, C#, Elixir, Python)
- Add PdfAnnotation types to TypeScript core bindings
- Add extract_annotations/margin fields to Ruby PdfConfig binding
- Export detectMimeFromBytes/getExtensionsForMime from WASM TypeScript bindings
- Remove stale kreuzberg-node artifacts/ directory
- Make PaddleOCR backend validation dynamic via plugin registry
- Fix Python tests expecting "json" to be invalid output format (now alias for "structured")
- Regenerate all e2e tests and re-vendor Ruby crates

Author: Goldziher

CHANGELOG.md

@@ -20,6 +20,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Fixed
 
 - PDF table recognition now validates column alignment, preventing body text pages from being misclassified as tables
+- PaddleOCR backend validation now dynamically checks the plugin registry instead of hardcoding, preventing false "backend not registered" errors when the plugin is available (#403)
+- WASM bindings now export `detectMimeFromBytes` and `getExtensionsForMime` MIME utility functions
+- Node.js NAPI-RS binding correctly exposes `annotations` field on `ExtractionResult`
+- Python output format validation tests updated to reflect `json` as a valid format (alias for `structured`)
 
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