[CI] Add a fresh-clone smoke test for `./setup.sh` and `./start.sh`

[utksh1]

Summary

The contributor setup path is documented as the primary onboarding flow, but CI does not appear to verify it end-to-end from a fresh clone.

Scope

• Add a lightweight smoke test for the scripted setup path.
• Keep it strict enough to catch onboarding regressions without turning CI into a full deployment environment.
• Document any environment assumptions.

Acceptance criteria

• CI exercises the scripted setup path at least once.
• Failures point clearly to onboarding regressions.
• The smoke test remains maintainable.

[siddiqui7864]

@utksh1 I'd like to work on this issue too.

I can add a GitHub Actions workflow that:

1. Runs ./setup.sh in a fresh Ubuntu environment
2. Verifies all dependencies install correctly
3. Runs ./start.sh and checks that services respond

Let me know if that approach works.

[anshul23102]

Interested in contributing to this under NSoC'26. This is a valuable issue addressing important functionality/quality. Happy to take this on.

/assign

[anshul23102]

Interested in contributing under NSoC'26. This is a valuable issue. Happy to work on it.

/assign