Playwright stack traces

Playwright stack traces provide lots of useful information, but something about them is overriding or otherwise preventing the exact failed test block and line. We should handle that so users don't have to drop break points and hunt OR trace the failure from the selector back up to the block/line.

Note: Could be related to issue 95 as this wasn't a problem in a VS Code project that used MSTest setup/teardown.

The issue names Playwright and a possible relationship to issue 95, but no source file, test, or entry point. Reproduce a failing Playwright test, compare its stack trace with the exact failed test block and line, and use issue 95 as context; done means the trace identifies that block and line without breakpoint-based tracing.

索引モデルが issue の本文から書いたものです。