Run JavaScript before every test, with Environment Init Scripts

Some test environments need setup that's not really about the test itself. A captcha to bypass, a tracker to silence, a flag to flip. Init Scripts handle that.

• Per-environment configuration: define a custom JavaScript snippet on any environment from environment settings.
• Runs automatically: Thunders executes the script before every test in that environment, no manual setup per test case.
• Common use cases: bypass client-side captcha and anti-bot gates, disable or stub analytics and trackers, or pre-seed feature flags.

If you've been working around a captcha in dev, polluting your analytics with test traffic, or manually toggling feature flags before each run, this handles it cleanly at the environment level.