Add the `com.apple.developer.web-browser` entitlement to enable native
password autofill from iCloud Passwords and third-party Credential
Provider Extensions (e.g. 1Password) in the browser panel's WKWebView.
This entitlement tells macOS that cmux functions as a web browser,
allowing the system to provide credential autofill suggestions on
password fields for any domain — the same mechanism Safari uses.
Note: this is a restricted entitlement that requires Apple's approval
via a provisioning profile. Until approved, the entitlement will be
present in the binary but inactive at runtime.
Hardened runtime's library validation was verifying every dylib on load,
causing noticeable UI lag. Add entitlements file with
disable-library-validation to fix while keeping notarization support.