Function apply_step_environment_updates 

pub fn apply_step_environment_updates(
    job_env: &mut HashMap<String, String>,
    job_user_env: &mut HashMap<String, String>,
    step_outputs_map: &mut HashMap<String, HashMap<String, String>>,
    step_id: Option<&str>,
)

Apply environment updates from a completed step to the job state.

• Stores step outputs keyed by step ID (for ${{ steps.<id>.outputs.<key> }})
• Merges GITHUB_ENV entries into job_env
• Prepends GITHUB_PATH entries to the PATH in job_env
• Clears per-step files so the next step starts fresh