install-browser is a no-op: always prints 'Browser ... is not installed' for the browser it was told to install

Start at the playwright-cli install-browser entry point and compare its browser resolution with npx playwright install chromium and the shared Playwright cache. Reproduce with Chromium and Firefox, then verify that installation downloads the matching build and that a subsequent playwright-cli open --browser=chromium succeeds.

playwright-cli install-browser <browser> does not install anything and always answers as if it were the "not installed" error, on this machine and for every browser kind.

Reproduced 2026-09-19, macOS 25.5.0 arm64:

$ playwright-cli --version
1.59.0-alpha-1771104257000

$ playwright-cli open --browser=chromium https://example.com
Browser "chromium" is not installed. Run `playwright-cli install-browser chromium` to install

$ playwright-cli install-browser chromium
Browser "chromium" is not installed. Run `playwright-cli install-browser chromium` to install

Observed behaviour:

• install-browser performs no download and exits with the "not installed" message for the browser it was told to install (the message even names chromium when invoked with firefox).
• npx playwright install chromium succeeds and populates the standard cache (~/Library/Caches/ms-playwright/chromium-1243, chromium_headless_shell-1243), but playwright-cli open --browser=chromium still reports "chromium is not installed" — the alpha CLI appears to expect a different registry/revision or a daemon restart that playwright-cli kill-all does not fix.

Expected: install-browser chromium downloads the matching browser build and a subsequent open succeeds.

Workaround used: drive the same flows through the playwright npm package directly (npm i playwright && node script.mjs), which resolves chromium-1243 from the shared cache.