Change HyperDX references to ClickStack in docs

[gingerwizard]

Updated deployment instructions and environment variables for ClickStack.

Wait for repo to be public before merging please. Will indicate.

Summary

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

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Preview	Comments	Updated (UTC)
clickhouse-docs	Ready	Preview	Comment	Nov 25, 2025 10:53am
clickhouse-docs-jp	Building	Preview	Comment	Nov 25, 2025 10:53am

2 Skipped Deployments

Project	Deployment	Preview	Comments	Updated (UTC)
clickhouse-docs-ru	Ignored	Preview		Nov 25, 2025 10:53am
clickhouse-docs-zh	Ignored	Preview		Nov 25, 2025 10:53am