Rename all crate directories, package names, binary names, proto
package/module paths, ALPN strings, env var prefixes, config filenames,
mDNS service names, and plugin ABI symbols from quicproquo/qpq to
quicprochat/qpc.
Swift SDK: Swift Package wrapping libquicproquo_ffi with QpqClient class
(connect, login, send, receive, disconnect) for iOS 15+ / macOS 13+.
Kotlin SDK: JNI bridge to libquicproquo_ffi with QpqClient class for
Android (aarch64, armv7) and JVM, Gradle build configuration.
Adds RegisterPushToken RPC (method ID 710) to device.proto for
APNs/FCM/WebPush device push token registration.
