docs(api): resolve Sphinx roles and hide private API members (NVBug 6628858)

[kheiss-uwzoo]

Summary

• Stop publishing raw Sphinx :class: / :meth: markup on the API reference by converting roles at MkDocs build time.
• Generate only the public ingest, retrieve, client, and parameter surfaces, and state the current 26.08 import paths.
• Hide private members and duplicate re-exports (_buffers, __all__, repeated EmbedParams).

Fixes NVBug 6628858.

Test plan

• Built the API page and confirmed Retriever / generate() / judge() show readable linked names instead of :class: text.
• Confirmed EmbedParams appears once at nemo_retriever.common.params.EmbedParams.
• Confirmed private headings (_buffers, _not_implemented, __all__) are absent.
• Review the generated API page in the docs preview.

pre-draft: leakage, mkdocs --strict, ::a, ::p, ::r on the diff vs main

Base: upstream/main
Files: nemo-retriever-api-reference.md, mkdocs.yml, sphinx_roles.py

Check	Result
Leakage (page roles + see [ CTAs)	PASS for this change — no see [ on the API page; no nimOperator on faq.md, overview.md, or multimodal-extraction.md. Script also flagged untracked leftover custom-metadata.md, which is not in this diff.
Allowed paths	PASS for the published page — 1 extraction markdown file. mkdocs.yml and sphinx_roles.py are docs-build files for this API-page fix.
mkdocs --strict	FAIL — exit 1; 4 warnings on untracked leftover pages that are not in this diff. The API page is not among those warnings.
::a audit	PASS — 7 import-path claims checked against src/ (95%). Code drift remains in retriever.py Sphinx roles.
::p polish	Applied — converted import-path sentences into a lead-in plus a parallel list.
::r style	95% — no blocking issues

Code drift (not in this docs PR): nemo_retriever/src/nemo_retriever/graph/retriever.py:73 still documents nemo_retriever.params.EmbedParams; :645 still documents nemo_retriever.llm.clients.LiteLLMClient; :699 still documents nemo_retriever.llm.clients.judge.LLMJudge. The published page rewrites those roles at build time.

[greptile-apps]

Greptile Summary

The PR narrows the generated API reference to selected public NeMo Retriever surfaces and adjusts mkdocstrings defaults to hide private, inherited, and duplicate members.

• Replaces broad module documentation directives with explicit ingest, retrieval, evaluation-client, and parameter directives.
• Documents the supported public import paths and API usage.
• Restricts mkdocstrings to the nemo_retriever source tree and public members.

Confidence Score: 5/5

The PR appears safe to merge.

No blocking failure remains.

Important Files Changed

Filename	Overview
docs/docs/extraction/nemo-retriever-api-reference.md	Reorganizes the generated API section around explicit public objects and documented import paths.
docs/mkdocs.yml	Configures mkdocstrings to use the NeMo Retriever source tree and suppress private, inherited, and submodule members.

_{Reviews (2): Last reviewed commit: "Merge branch 'main' into docs/6628858-ap..." | Re-trigger Greptile}