1.37.0 release

Bug fixes:
- Update korg-clang-22 to 22.1.0
- Update korg-clang-22 to 22.1.1
- Update korg-clang-22 to 22.1.2
- runtime: null: check if compiler exists on host
- build: raise CompilerNotFoundError for null runtime
- build: replace korg arch if/elif chain with a dict
- arch: loongarch: move LLVM vars to clang toolchain configs
- korg-gcc: use kernel arch names for targets
- arch: powerpc: switch CROSS_COMPILE to powerpc64-linux-gnu-
- korg-gcc: add powerpc support
- toolchain: remove llvm, korg-llvm, and rustllvm
- target: drop CC and HOSTCC for kselftest clang builds

Container images:
- Revert "runtime: docker: Apply workaround for apt.llvm.org installation errors on Trixie"
- docker: Dockerfile.build: handle libfuse-dev to libfuse3-dev transition