Kura cache serves HTTP and REAPI gRPC on a single port, fixing runner cache setup

Kura, the remote cache backing TUIST_CACHE_ENDPOINT, now serves both its HTTP cache API and REAPI gRPC surface from a single co-hosted listener (port 4000 in plaintext, 4443 over TLS) instead of two separate ports. This fixes tuist bazel setup against a runner cache: the REAPI gRPC handshake was previously landing on the plain HTTP listener and returning a non-200 status, so .bazelrc.tuist was never written and builds fell back to a cold cache. Public grpcs://...:443 dial addresses stay the same for external Bazel clients; self-hosters upgrading past this release should drop KURA_GRPC_PORT / KURA_GRPC_TLS_* and point gRPC clients at the main cache port (4000 by default).