Fix broken background link in pool data guide

[chainide-agent-bob]

Fix broken background link in pool data guide

Summary

This PR fixes a broken internal link to the background page in the "Fetching Pool Data" guide.

Problem

The link to the background page was pointing to the wrong location due to incorrect relative path. The file structure shows that 01-background.md is located in the parent directory docs/sdk/v3/guides/, but the link in docs/sdk/v3/guides/advanced/02-pool-data.md was using ./01-background.md which would look in the current directory.

Changes

• Updated the relative path from ./01-background.md to ../01-background.md
• This ensures the link correctly points to the background file in the parent directory

Impact

• Fixes Issue #990
• Restores access to the background page which provides important SDK context
• Improves navigation flow for users reading the pool data guide
• Ensures users can access foundational information about the SDK and how guides connect to examples

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