feat: add capture-output input to prevent GHA memory limit failures

[simple-agent-manager]

Summary

• Adds a capture-output input (default: true) that controls whether the command's stdout is captured as a step output
• When disabled, the command runs directly without buffering stdout into $GITHUB_OUTPUT, avoiding the GitHub Actions memory limit error:

  The maximum allowed memory size was exceeded while evaluating the following expression: steps.command.outputs.stdout
  

• Full output is still visible in the workflow logs regardless of this setting

Context

Large Pulumi deployments (e.g. Portal staging with 125+ events) produce enough output to exceed GHA's expression evaluation memory limit. The deploy succeeds but the workflow fails, which blocks downstream jobs like production deployment.

No existing consumers of this action use outputs.stdout, so this is a safe default-on addition.

Usage

- name: Deploy
  uses: DefangLabs/defang-github-action@v2
  with:
    capture-output: false

Test plan

• CI passes on this branch (existing tests use default capture-output: true)
• Verify Portal deploy workflow works with capture-output: false after merge

🤖 Generated with Claude Code