chore: doc update 26.1.2

[rollandf]

No description provided.

[greptile-apps]

Greptile Summary

The PR promotes the documentation from the 26.1.2 release candidate to the final 26.1.2 release.

• Updates production image repositories, component tags, driver versions, and image digests.
• Regenerates processed deployment examples with the final release coordinates.
• Adds the 26.1.2 release note and updates repository documentation metadata.

Confidence Score: 5/5

The PR appears safe to merge with its release metadata, documentation, and processed examples aligned to version 26.1.2.

No concrete build failure, invalid release coordinate, generated-file inconsistency, or other actionable defect was established in the changed files.

Important Files Changed

Filename	Overview
docs/common/vars.rst	Updates shared release substitutions to the final 26.1.2 versions and production registries consistently.
docs/advanced/images-sha256.rst	Replaces release-candidate image coordinates and digests with the final release image inventory.
docs/customizations/helm.rst	Aligns documented Helm defaults with the final production repositories and component tags.
examples/processed/ipoib-rdma-shared/complete.yaml	Regenerates the representative full deployment example using the final driver and component images.
docs/release-notes.rst	Adds the 26.1.2 maintenance-release entry.
repo.toml	Advances the documentation project version from v26.1.1 to v26.1.2.

_{Reviews (1): Last reviewed commit: "chore: doc update 26.1.2" | Re-trigger Greptile}

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Documentation preview

https://mellanox.github.io/network-operator-docs/review/pr-405