2.11.0

(feat): Add opt-in support for a structured User-Agent header on generated SDK clients, gated behind a new includePlatformHeaders config option (default off, so existing generated output is unchanged). When enabled, the client reports its SDK name/version plus the operating system, architecture, and PHP runtime version in the Twilio-style shape {sdkName}/{sdkVersion} ({os}; {arch}) PHP/{runtimeVersion} (e.g. my-sdk/1.0.0 (linux; x86_64) PHP/8.2.0). The platform values are resolved at runtime via PHP_OS, php_uname('m'), and PHP_VERSION. Unknown segments are omitted gracefully (the (os; arch) group is dropped when both are empty, a single known value is included on its own, and the version suffix is dropped when unavailable), and the discrete X-Fern-Platform / X-Fern-Runtime headers are consolidated into the User-Agent.