[general-purpose] Add test run counter

[sylvansys]

Parent Issue: #311
Agent Type: general-purpose
Branch: 311-fix/can-u-test-out-the-gh-orchestration-plug

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Task Description

Add test run counter

Task Prompt

Add a third function to plugins/github-orchestration/tests/utils/test-helpers.ts:

let testCounter = 0;

export function getNextTestId(): string {
  testCounter++;
  return `test-${testCounter}`;
}

Add this after the existing functions. Keep the file simple.