[aik099]

Playwright can launch a browser binary it doesn't manage through the executablePath launch option, but there was no way to set it from PHP. That's needed for Chromium-based browsers that aren't a Playwright channel, such as Brave or a locally built Chromium.

This picks up #101 by @feder-cr, which was closed when its fork was deleted, and adds the tests asked for there.

Updates:

• BrowserBuilder::withExecutablePath() sets the executablePath launch option;
• PlaywrightConfig::$executablePath, PlaywrightConfigBuilder::withExecutablePath() and PW_EXECUTABLE_PATH, applied in PlaywrightClient::createBrowserBuilder() the same way as channel; an explicit setter call wins over the config;
• a "Launch a browser from a custom path" section in docs/guide/browsers.md.

When it isn't set, nothing is added to the launch payload.

Tested by hand with Brave 155 on macOS through playwright-mink, which ran the Mink driver test suite in it.

🤖 Generated with Claude Code

[aik099]

The 4 integration failures (RouteTest::testCanRedirectNavigationRequest*) aren't from this change: they fail on main too with Playwright 1.64, as in the Nightly runs since Oct 8. #186 fixes them.