Remove unecessary claude PR review bot (#1361)

Keeps `@\claude` support but drops the auto PR reviews by claude, we
already have plenty of auto-review feedback from greptile and cubic.

<!-- This is an auto-generated description by cubic. -->
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## Summary by cubic
Removed the Claude PR review GitHub Action to stop automatic reviews.
Keeps @claude support and reduces duplicate bot feedback, since greptile
and cubic already provide auto-review.

<sup>Written for commit 740d927.
Summary will update automatically on new commits.</sup>

<!-- End of auto-generated description by cubic. -->

Author: pirate