Default behavior unchanged. Users can opt in via pdf_parser="pypdfium2"
for cleaner text extraction (no broken words, correct Unicode) and
3-5x faster parsing. PyPDF2 remains the only required dependency;
pypdfium2 is lazy-imported.
* Consolidate tests/ into examples/documents/
* Add line_count and reorder structure keys
* Lazy-load documents with _meta.json index
* Update demo script and add pre-shipped workspace
* Extract shared helpers for JSON reading and meta entry building
* Add PageIndexClient with retrieve, streaming support and litellm integration
* Add OpenAI agents demo example
* Update README with example agent demo section
* Support separate retrieve_model configuration for index and retrieve
