Default LLM to Hugging Face on Spaces; fix HF_TOKEN settings merge

Enhance Docker configuration and Hugging Face integration

Enhance environment configuration and API documentation for Milestone 11

Implement Milestone 7 by introducing background ingestion jobs. Update environment configuration to include job database path, enhance job tracking with new endpoints, and refactor ingestion logic to support asynchronous processing. Modify response models to include job details and ensure proper initialization of the jobs database on startup.

Enhance configuration and ingestion functionality for Milestone 4. Update .env.example with new environment variables, expand milestones documentation with integration details, and add necessary dependencies to pyproject.toml and requirements.txt. Refactor ingest and query routes to support file uploads and retrieval, implementing validation and error handling. Update settings to include new model configurations and parameters for chunking and embedding.

Implement Milestone 3 by adding configuration and request/response contracts. Introduce new models for requests and responses, enhance route handlers with schema validation, and update dependencies to include pydantic-settings. Update audit, ingest, jobs, and query routes to utilize new models and improve response structures.