docs(extraction): add 26.08 release notes for post-26.05 changes

[kheiss-uwzoo]

Summary

• Replace the retitled 26.05 body on main with customer-facing 26.08 / 26.8.0 highlights for functionality that landed after 26.5.0.
• Compared upstream/main (including 26.08-RC2) against the 26.05 scope (tag 26.5.0 / published 26.05 notes). Dropped items already claimed in 26.05 (CLI ingest/query as new, experimental subcommands, torch 2.11, OCR language selectors, leftover pipeline-CLI removal).
• Kept post-26.05 deltas: OCR v2 everywhere (Helm included), combined nemotron-object-detection:2.0.1, Omni as default caption, VL embed/rerank 2.3.0, agentic retrieval, text ingest, LanceDB hybrid/autodetect, Compose/Zipkin, Ray >=2.56.1 / macOS Intel drop.
• Added items on main that the prior draft missed: collection/document APIs, Secret-backed service auth, embedder model router, MCP query-method and rerank, extraction NIM performance mode, PDF render parameters, optional Super 49B agentic NIM.

Related

• Eng: Fix CVE pkgs #2440 (Ray bump + drop macos-x64 CI)
• Install guide / support matrix + README: draft docs: drop macOS Intel (x86_64) from supported client platforms #2441
• Collections: feat: add scoped collection and document management APIs #2378 / feat: extend collection lifecycle and document metadata #2436
• Service auth: service: add Secret-backed deployment authentication #2423

Out of scope

• Broader 26.08 version-string cutover across README/Helm (see draft docs: rebrand main docs to 26.08 for RC GitHub Pages QA #2430)
• Runtime/Helm chart defaults (already on main; this PR documents them only)
• Support-matrix / README platform wording (see docs: drop macOS Intel (x86_64) from supported client platforms #2441)

Test plan

• Review bullets against main vs 26.5.0 (not vs the old 26.08 draft)
• Confirm dropped 26.05 items are not restated as new
• Confirm Helm image tags match current values.yaml (OCR/OD 2.0.1, VL 2.3.0)
• Confirm macOS Intel drop bullets match Fix CVE pkgs #2440 / docs: drop macOS Intel (x86_64) from supported client platforms #2441
• Spot-check previous-version links still resolve

[greptile-apps]

Greptile Summary

The PR replaces the prior 26.05-oriented content with customer-facing 26.08 release notes and incorporates the requested follow-up corrections.

• Documents post-26.05 ingestion, service, model, agentic retrieval, vector database, packaging, and Helm changes.
• Clarifies that Development Compose retains older model tags while Helm uses the announced release defaults.
• Restores ingestion bullets beneath the Pipeline and ingestion section.

Confidence Score: 5/5

The PR appears safe to merge.

No blocking failure remains.

Important Files Changed

Filename	Overview
docs/docs/extraction/releasenotes.md	Reworks the 26.08 release notes and correctly resolves both prior documentation findings.

_{Reviews (2): Last reviewed commit: "docs(extraction): fix 26.08 RN Compose p..." | Re-trigger Greptile}