408f0d352f
Attaching to a long-running browser (a signed-in profile, an Electron app kept open for a session) meant repeating app.cdp_url on every browser call, and any call that omitted it silently launched a fresh headless Chromium instead. browser.cdpUrl supplies that endpoint once. It is a default rather than an override: app.cdp_url and app.path still win, and an unset or blank value leaves cmux and headless resolution exactly as before.