fix(setup,browse): support GSTACK_SKIP_PLAYWRIGHT and fix system chromium test execution

[joseironchip]

Description

This PR resolves the freezing and crashing issues during ./setup on non-Ubuntu Linux environments (such as Arch Linux or NixOS) when trying to bypass the default Playwright browser bundle download.

Changes

1. Core Pipeline Bypass: Implemented the GSTACK_SKIP_PLAYWRIGHT handling logic inside the main setup execution pipeline.
2. Smoke Test Resolution: Rewrote ensure_playwright_browser() under the skip parameter to temporarily append playwright locally to development dependencies (--dev) and map to GSTACK_CHROMIUM_PATH with a sandbox-free environment.
3. Test Suite Compatibility: Updated /browse/src/browser-manager.ts and /browse/test/bridge-chromium-e2e.test.ts to inherit GSTACK_CHROMIUM_PATH, adding explicit headless: true and sandbox arguments to ensure tests can pass successfully using the system browser.
4. Documentation: Added an advanced Linux installation section inside the README.md to guide Arch Linux/NixOS users.

Closes #913

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