docs(extraction): document --ray-log-to-driver instead of removed Ray log presets (NVBug 6620618)

[kheiss-uwzoo]

Summary

• Docs-only fix for NVBug 6620618. The Ray logging page documented INGEST_RAY_LOG_LEVEL presets (PRODUCTION, DEVELOPMENT, DEBUG) that were removed with the legacy nv-ingest framework. Setting the variable is a silent no-op on current main.
• Remove the preset quick start, the three preset sections, the configuration-table row, the invalid-value warning, and the examples that depended on the preset.
• Document the supported control: --ray-log-to-driver / --no-ray-log-to-driver on retriever ingest batch, and ray_log_to_driver on create_ingestor. Keep the nine upstream RAY_* environment variables.

Test plan

• Confirm INGEST_RAY_LOG_LEVEL no longer appears in published docs
• Confirm the page documents --ray-log-to-driver / --no-ray-log-to-driver as batch-only, default enabled
• Confirm Python examples use create_ingestor(run_mode=batch, ray_log_to_driver=False) and .ingest()
• Confirm the nine RAY_* rows remain and RAY_LOG_TO_DRIVER is described as not controlling the NRL batch ray.init(log_to_driver=...) path
• python -m mkdocs build --strict --config-file mkdocs.yml from docs/

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

Base: upstream/main
Files: ray-logging.md

Check	Result
Leakage (page roles + see [ CTAs)	PASS — no see [ CTAs; no nimOperator / nvcr.io/nim / installFfmpeg
Allowed paths	PASS — 1 documentation file
mkdocs --strict	PASS — exit 0 after hiding untracked leftover pages (custom-metadata.md, user-defined-stages.md) that are not in this diff
::a audit	PASS — INGEST_RAY_LOG_LEVEL absent from Python source; ray_log_to_driver default True; CLI flag is batch-only; ensure_local_ray_runtime passes log_to_driver to ray.init() (95%)
::p polish	Applied — replaced dead preset path with working CLI/Python control; kept RAY_* reference; glob-based .files() example
::r style	95% — no blocking issues

Code drift (not in this docs PR): none. The library does not read INGEST_RAY_LOG_LEVEL. Reimplementing the preset would be a separate eng PR.

Overlap: Draft PR #2606 also edits ray-logging.md (adds one Related Topics link). Resolve that one-line conflict if both land.

PR: draft against main