fix(ci): provision review Python with uv on CodeBuild

[notgitika]

Summary

• replace actions/setup-python in the harness review workflow because it has no Amazon Linux 2023 Python builds
• use setup-uv to download Python 3.12 and activate a virtual environment
• install boto3 into the activated environment

Verification

• npm run typecheck (via pre-commit hook)
• Prettier and secretlint (via lint-staged)
• Full workflow dispatch on the CodeBuild runner: https://github.com/aws/agentcore-cli/actions/runs/30049510856
  • downloaded and activated CPython 3.12.13
  • installed boto3 successfully
  • completed the harness review and cleanup successfully

[notgitika]

The automatic ai-review failure on this PR is the bootstrap failure fixed here: because this workflow uses pull_request_target, GitHub executes .github/workflows/pr-ai-review.yml from main, where it still calls unsupported actions/setup-python on Amazon Linux 2023.

I validated this branch's workflow directly on the same CodeBuild runner. The full run succeeded, including CPython 3.12.13 provisioning, boto3 installation, harness execution, and cleanup: https://github.com/aws/agentcore-cli/actions/runs/30049510856

[agentcore-devx-automation]

Claude Security Review: no high-confidence findings. (run)

[github-actions]

Package Tarball

aws-agentcore-0.24.2.tgz

How to install

gh release download pr-1823-tarball --repo aws/agentcore-cli --pattern "*.tgz" --dir /tmp/pr-tarball
npm install -g /tmp/pr-tarball/aws-agentcore-0.24.2.tgz

[github-actions]

Coverage Report

Status	Category	Percentage	Covered / Total
🔵	Lines	40.31%	15049 / 37333
🔵	Statements	39.56%	16039 / 40535
🔵	Functions	34.42%	2567 / 7457
🔵	Branches	33.71%	10022 / 29728

Generated in workflow #4198 for commit c091157 by the Vitest Coverage Report Action