Add categories to search widget

[paoloredis]

Note

Low Risk
Client-side display logic only in the search modal; no API, auth, or data changes.

Overview
Search results are now grouped under Blog, Tutorials, and Support when their URLs match redis.io/blog, redis.io/tutorials, or support.redislabs.com, instead of relying only on hierarchy[0].

A new deriveCategory helper in sortData drives both the unique category list and which hits appear under each section header in the modal.

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[github-actions]

DOC-6752

[CLAassistant]

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[jit-ci]

🛡️ Jit Security Scan Results

✅ No security findings were detected in this PR

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[cursor]

Cursor Bugbot has reviewed your changes and found 1 potential issue.

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[paoloredis]

Staging branch: https://redis.io/docs/staging/DOC-6752/

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Search widget results for support.redislabs.com, redis.io/tutorials and redis.io/blog are now categorized.
Before this change:

After this change: