feat: complete OracleDocumentStore operations

[yugborana]

…testing

Related Issues

• fixes OracleDocumentStore missing methods and test coverage #3172

Proposed Changes:

I finalized the Oracle integration by completing all missing Document Store functions, fixing underlying datatype bugs, and implementing their asynchronous equivalents using asyncio.to_thread to prevent thread-blocking during database calls.

How did you test it?

To ensure total reliability, we rely on 28 unit tests executing entirely in mocked memory to validate parsing logic and component structure, supplemented by 105 real-database integration tests driven by Haystack's strict compliance mixins proving complete systemic alignment. For manual verification, we orchestrated an end-to-end Python script that connects to the live Oracle 23ai Docker container, injects diverse real-world metadata, merges patches, manipulates keyword indexing, and audits the async output states.

Notes for the reviewer

Checklist

• I have read the contributors guidelines and the code of conduct - yes
• I have updated the related issue with new insights and changes - yes
• I added unit tests and updated the docstrings - yes
• I've used one of the conventional commit types for my PR title: fix:, feat:, build:, chore:, ci:, docs:, style:, refactor:, perf:, test:. - yes

[CLAassistant]

All committers have signed the CLA.

[yugborana]

@davidsbatista @julian-risch

[yugborana]

@bogdankostic @sjrl

[davidsbatista]

@yugborana, thanks for your contribution. I will start the review still this week.

NOTE: There's no need to tag anyone immediately; once the PR is open, one of us will be assigned to review it.

[yugborana]

Thanks for the reply. Sorry for tagging immediately.