ci(docs): publish on release and stop fork PRs failing on comment

[michalharakal]

What

Two documentation-workflow fixes.

docs.yml — publish docs on release

• Deploy the Antora site to GitHub Pages on release: published instead of on every push to develop, so the live site tracks the last released version.
• build-docs still runs on PRs/pushes for validation; only the deploy trigger moved.
• The release event is immune to the paths: filter and checks out the released commit, where generateDocs/dokkaGenerate run live against the working tree — so no generated pages need to be committed. Single-version for now.

documentation.yml — stop fork PRs failing on the preview comment

• The "Create PR comment with preview link" step failed on fork PRs (e.g. [DOC]: Pin docker image with hash #846, [DOCS]: Pin npm packages with their commit hash in Dockerfile #848) because such PRs get a read-only GITHUB_TOKEN regardless of the workflow's permissions: block.
• Guard the step to same-repo PRs (github.event.pull_request.head.repo.full_name == github.repository) and mark it continue-on-error so a missing comment never fails the run.

Why

• Under heavy development, the public docs site should reflect the last release, not drift ahead on every develop push.
• Fork PRs that touch docs were showing a red X on an unrelated, non-fatal step.

Scope / follow-up

• Deliberately single-version for now. Full multi-repo, versioned Antora aggregation is tracked in [Feature]: multi-repo, versioned Antora documentation aggregation site #849 (DARC).
• Does not touch docs/antora.yml (version: ~ unchanged).

Testing notes

• YAML validated for both workflows; merge conflict against develop's newly SHA-pinned actions resolved (kept the pinned github-script SHA).
• The release-deploy path can only be fully exercised by publishing a release; build-docs continues to run on this PR.

[github-actions]

📖 Documentation Preview

The documentation has been built successfully for this PR.

Generated Files:

• Operator documentation: docs/modules/operators/_generated_/
• JSON schema output: operators.json

Artifacts:

• Download the documentation-preview-850 artifact to view the complete documentation locally.

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