Issue Description

We validated the copilot-setup-steps.yml are applied as custom environment for Copilot Cloud coding agent (see agent sessions for this). However copilot-setup-steps.yml workflow have push and pull_request path triggers that caused it to run as a visible GitHub Actions workflow when the file changed. This is not the intended behavior because:

1. Copilot coding agent runs setup steps internally before starting work, not as a triggerable workflow
2. The visible workflow runs in Actions tab were unrelated to Copilot's actual use of the setup steps

Required Changes

1. Remove push and pull_request path triggers, keeping only workflow_dispatch
2. Add continue-on-error: true to npm ci step so Copilot can still start work even if dependency installation fails (allowing it to fix the issue), this is based on guidance per MAUI team learnings

Verification

To confirm Copilot is using setup steps:

1. Assign an issue to Copilot or use @copilot on a PR
2. Go to https://github.com/copilot/agents (agents tab)
3. Click on the session and view session logs
4. Look for "Setup Steps" execution at the beginning of the session

Additional Context

From MAUI team guidance: "Copilot (or a human) might push a commit that breaks the build. If you leave a comment like @copilot fix error XYZ, it needs to be able get past its setup steps and actually fix the problem."
Reference: https://devblogs.microsoft.com/dotnet/maui-team-copilot-tips/

This context is useful background information for future build steps we may want in the environment.