Update backend run instructions in docs

[areibman]

📥 Pull Request

📘 Description
Added a new guide (docs/v2/usage/self-host-backend.mdx) providing comprehensive instructions for running the full AgentOps backend platform (API, dashboard, ClickHouse, OTEL Collector) from the app/ directory. This includes steps for Docker Compose and native development. The new page has been integrated into the v2 documentation navigation.

🧪 Testing
The new documentation was reviewed for clarity, completeness, and accuracy of the provided instructions. The integration into the docs/mint.json navigation was verified to ensure the page appears correctly in the sidebar.

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[cursor]

Cursor Agent can help with this pull request. Just @cursor in comments and I'll start working on changes in this branch.
_{Learn more about Cursor Agents}

[github-actions]

This pull request has been automatically marked as stale because it has not had any activity in the last 14 days.

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