revert: remove buildspec.yml and codebuild.yml changes from docs PR

Revert CI/CD file changes that are out of scope for this
documentation remediation PR:

- Remove buildspec.yml (new file — should be tracked separately)
- Revert codebuild.yml spelling fixes and sts identity command
  (infrastructure changes, not documentation)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: scottschreckengaust