[Feature Request]: Expose full Playwright launch and context parameters in BrowserConfig

[Melodeiro]

What needs to be done?

Expose standard Playwright chromium.launch() and browser.new_context() parameters that are currently not accessible through BrowserConfig:

1. executable_path — path to a custom Chromium binary
2. ignore_default_args — list of default Chromium flags to exclude from launch
3. A way to opt out of hardcoded launch args (e.g. --disable-gpu, --disable-gpu-compositing) that _build_browser_args() always includes
4. A way to skip forced header overrides — setup_context() always sets User-Agent and sec-ch-ua via set_extra_http_headers, overriding whatever the browser natively reports
5. A way to skip navigator_overrider.js injection independently of override_navigator when the binary already handles these properties natively
6. device_scale_factor — currently hardcoded to 1.0 in create_browser_context()

What problem does this solve?

Custom Chromium builds (ungoogled-chromium, Brave, stealth-patched binaries, etc.) manage their own fingerprinting at the C++ level — user agent, WebGL renderer, device scale factor, navigator properties, and so on. When Crawl4AI overrides these values at the Playwright layer, it creates detectable mismatches:

• The binary reports one user agent natively, but Crawl4AI forces a different one via HTTP headers
• The binary sets navigator.webdriver = undefined at the engine level, but navigator_overrider.js re-patches it via Object.defineProperty — which anti-bot systems detect through toString() and getOwnPropertyDescriptor()
• --disable-gpu prevents hardware-accelerated WebGL, which changes the rendering fingerprint the binary was designed to produce
• device_scale_factor: 1.0 may conflict with what the binary reports via window.devicePixelRatio

The net effect is that the browser's built-in stealth gets partially undone by the crawler layer on top of it.

Target users/beneficiaries

Anyone using Crawl4AI with a custom Chromium binary — whether for anti-detection, testing, or enterprise browser builds — where the binary manages its own configuration and the crawler should not override it.

Current alternatives/workarounds

There is no clean workaround within the public API. The hardcoded args in _build_browser_args(), the forced User-Agent/sec-ch-ua headers in setup_context(), and the device_scale_factor in create_browser_context() are not configurable. The only option is to fork or monkey-patch BrowserManager.

Proposed approach

One possible approach (open to other ideas):

• Add executable_path: str = None and ignore_default_args: list = None to BrowserConfig, pass them through to chromium.launch()
• Add something like skip_default_browser_args: bool = False that, when set, skips the hardcoded args list in _build_browser_args() and only uses extra_args
• Add skip_default_headers: bool = False to skip the forced User-Agent/sec-ch-ua override in setup_context()
• Make device_scale_factor a configurable field in BrowserConfig instead of hardcoded 1.0

This keeps full backward compatibility — all defaults stay the same — while giving users of custom binaries full control when they need it.