mcpp:plugins 0.2.0

Two new rule packages and a route that had no payload behind it.

mcpp.rules.sycl (feature rules-sycl, mcpp >= 2026.9.6.1) drives the
xim:dpcpp payload over .sycl translation units. It submits one compile
action per source and one that consumes their outputs, because a SYCL object
carries its device image and nothing registers it until -fsycl-link emits a
wrapper.

mcpp.rules.hip (feature rules-hip, mcpp >= 2026.9.5.2) compiles .hip
units on the NVIDIA platform, where HIP is a header layer over the CUDA
runtime: the compiler is the project's own clang and there is no ROCm on the
machine. The AMD platform is refused by name with the reason.

mcpp.rules.spirv gains the glslc route. Its own source used to say the route
was unsupported "because nothing in this ecosystem publishes it, and a route
with no payload behind it is a claim rather than a feature". xim:shaderc now
publishes one.

Measured on an RTX 4080: both new lanes answer 12 24 36 48 on the device and
again under --no-accel, with no host C++ standard library on any device
compile.