Docs: sync upstream clickhouse-operator docs updates

[mintlify]

Summary

Sync Keeper leadership handover docs from ClickHouse/clickhouse-operator#351.

Changes

• products/kubernetes-operator/guides/configuration.mdx: add "Leadership handover on termination" section (default preStop hook using ydld).
• products/kubernetes-operator/reference/api-reference.mdx: add lifecycle field to ContainerTemplateSpec.

Context

Copied verbatim from upstream commit 09774ab. Review requested from the upstream author, Muhammad Soliman (commit email devadel@gmail.com). I couldn't find their GitHub handle, so please add them as a reviewer by hand.

Notes / issues (fix upstream first)

• The new section uses em dashes as clause joiners ("...container stop — a fire-and-forget..." and "...containerTemplate.lifecycle — see"). This goes against the style guide.
• The upstream commit message says yldl, but the docs and PR description say ydld. Please confirm the correct command name.
• The configuration guide overlaps with open PR Docs: sync upstream clickhouse-operator docs updates #117732 (a different section). A small merge conflict is possible.
• Translated copies (ar, es, fr, ja, ko, pt-BR, ru, zh) were not updated.
• The #containertemplatespec anchor is present. The full broken-links check timed out, so link checking was not completed.

Changelog category (leave one):

• Documentation (changelog entry is not required)

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Workflow [PR]
Sync PR [sync-upstream/pr/123072]

Version info

• Merged into: 26.10.1.1097-master (included in 26.10 and later)

[mintlify]

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Project	Status	Preview	Updated
ClickHouse-docs	🟢 Ready	View Preview	Sep 30, 2026, 2:32 PM

[clickhouse-gh]

Workflow [PR], commit [83bf8ef]

Summary: ✅

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AI Review

Summary

This PR syncs the upstream Keeper leadership-handover docs into the operator guide and adds lifecycle to the ContainerTemplateSpec API reference. The API-reference addition looks consistent, but the new guide now documents the handover hook as a no-op before 26.3; repository history shows both ydld and the Keeper http_control commands endpoint existed much earlier, so the compatibility contract is currently wrong.

Findings

⚠️ Majors

• [docs/products/kubernetes-operator/guides/configuration.mdx:91-93] The new compatibility note overstates the minimum supported Keeper version. ydld was introduced in 361472b29e06 on 2023-11-06, and the Keeper http_control commands endpoint in bc50b68f0558 on 2024-05-13, both well before the 26.3 release line. As written, the guide tells operators on older releases to expect a no-op even though the handover command path should already exist.
  Suggested fix: replace 26.3 with the actual version or capability boundary the hook depends on, or remove the explicit version floor until it is verified.

Final Verdict

• Status: ⚠️ Request changes
• Minimum required action: correct the documented compatibility floor for the Keeper leadership-handover preStop hook.

[clickhouse-gh]

This compatibility floor looks wrong. ydld itself was added in 361472b29e06 (2023-11-06), and the Keeper http_control commands endpoint landed in bc50b68f0558 (2024-05-13), so versions well before 26.3 already expose the command path this hook uses. As written, the guide tells users on earlier releases to expect a no-op when the handover hook should already work. Please either document the real minimum version/capability boundary here or drop the 26.3 claim.