ci: remove claude-code-review workflow

CCR now handles code review on this repo (since ~2026-03-08), making
this workflow redundant. The workflow has been running on every PR push
but cannot post reviews due to read-only pull-requests permissions, so
it was consuming compute without producing visible output.

The claude.yml workflow for @claude mentions is retained. #2337 already
added the '@claude review' exclusion guard so it does not overlap with
CCR.

Matches typescript-sdk#1754.

Author: maxisbey