Improvement: update TTL doc with best practice

[Blargian]

Summary

Update doc with a best practice section based on docs channel ask

Checklist

• Delete items not relevant to your PR
• URL changes should add a redirect to the old URL via https://github.com/ClickHouse/clickhouse-docs/blob/main/docusaurus.config.js
• If adding a new integration page, also add an entry to the integrations list here: https://github.com/ClickHouse/clickhouse-docs/blob/main/docs/integrations/index.mdx

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Project	Deployment	Review	Updated (UTC)
clickhouse-docs	Ready	Preview	Jan 6, 2026 10:47am

2 Skipped Deployments

Project	Deployment	Review	Updated (UTC)
clickhouse-docs-ru	Ignored	Preview	Jan 6, 2026 10:47am
clickhouse-docs-zh	Ignored	Preview	Jan 6, 2026 10:47am