feat(zookeeper): add 3.8.6 and 3.9.5 versions

[weicao]

Summary

• add ZooKeeper service versions 3.8.6 and 3.9.5 to the addon ComponentVersion matrix
• update ZooKeeper README, examples README, example valid-options comment, and root addon list
• keep existing older versions and the default 3.7.2 tag unchanged for compatibility

Validation

• SDD checked KB 1.2/main addon API docs: docs/addon-api/README.md, 04-component-version.md, 12a-minimum-acceptance.md
• helm dependency build ./addons/zookeeper
• helm lint ./addons/zookeeper
• helm template zk ./addons/zookeeper
• helm template zk ./addons/zookeeper --set images.tag=3.8.6
• helm template zk ./addons/zookeeper --set images.tag=3.9.5
• rendered ComponentVersion contains docker.io/apecloud/zookeeper:3.8.6 and :3.9.5 image mappings
• version consistency script passed
• bash -n addons/zookeeper/scripts/.sh addons/zookeeper/dataprotection/.sh addons/zookeeper/scripts-ut-spec/*.sh
• git diff --check

Runtime boundary

This PR only declares addon support and docs for 3.8.6 / 3.9.5. Runtime PASS still depends on publishing compatible apecloud/zookeeper:3.8.6 and apecloud/zookeeper:3.9.5 images, then running smoke/function validation for both versions.

[weicao]

Addressed the review feedback on this PR.\n\nWhat changed:\n- Removed the unrelated ClickHouse README diff by resetting the PR head to the clean Zookeeper branch.\n- Bumped the Zookeeper chart version from 1.2.0-alpha.0 to 1.2.0-alpha.1 because the rendered ComponentVersion changes.\n\nValidation:\n- helm dependency build ./addons/zookeeper\n- helm lint ./addons/zookeeper\n- helm template zk ./addons/zookeeper\n- helm template zk ./addons/zookeeper --set images.tag=3.8.6\n- helm template zk ./addons/zookeeper --set images.tag=3.9.5\n- bash -n addons/zookeeper/scripts/.sh addons/zookeeper/dataprotection/.sh addons/zookeeper/scripts-ut-spec/*.sh\n- git diff --check\n\nUpdate commit: 765af1a.\nCurrent PR diff is now limited to Zookeeper/root README files; no ClickHouse diff remains.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 0.00%. Comparing base (581524d) to head (765af1a).

Additional details and impacted files

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  Coverage   0.00%   0.00%           
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  Files         73      73           
  Lines       9270    9270           
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  Misses      9270    9270           

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[weicao]

CI update after head 765af1a:\n\nThe remaining failing chart checks are blocked by missing runtime image tags, not by Helm rendering or shell syntax. The failed job logs show:\n\n- docker.io/apecloud/zookeeper:3.9.5 is not exists.\n- docker.io/apecloud/zookeeper:3.8.6 is not exists.\n\nChecks that passed on this head include shell-check, shellspec-test, generate-files, and check-addons-cluster-helm. Local offline validation also passed for default render, 3.8.6 render, and 3.9.5 render.\n\nBoundary: this PR is ready for the image lane to produce/publish apecloud/zookeeper:3.8.6 and apecloud/zookeeper:3.9.5; runtime verification for the new service versions will run after those tags are available.