feat(spawn-jdk): tag JDK with target OperatingSystem and Architecture

[deer]

JDK previously only tracked its JDKVersion and JDKHome, with no way to tell which platform a given installation was actually built for. This made it impossible to distinguish a foreign JDK -- for example one staged for cross-target jlinking -- from a JDK native to the host running detection.

This adds two new enums, OperatingSystem (LINUX, MAC, WINDOWS, OTHER) and Architecture (X86_64, AARCH64, OTHER), each with an of(String) parser for common naming variants and a current() factory sourced from the os.name/os.arch system properties. JDK now carries an operatingSystem() and architecture() alongside its version and home, with equals()/hashCode()/toString() updated to match; the existing of(version, home) and current() factories keep working by defaulting to the host's current platform.

JDKDetector.of(Path) now reads the OS_NAME/OS_ARCH entries from a JDK's release file to tag it with the platform it was built for, falling back to the host's current platform when those entries are absent, preserving prior behavior. A new default method, JDKDetector.detect(OperatingSystem, Architecture), filters the detected JDKs down to a specific target platform.