feat: migrate from Cedar to SpiceDB authorization system

This is a major architectural change that replaces the Cedar policy-based
authorization system with SpiceDB's relation-based authorization.

Key changes:

- Migrate from Rust to Go implementation
- Replace Cedar policies with SpiceDB schema and relationships
- Switch from envoy `ext_authz` with Cedar to SpiceDB permission checks
- Update build system and dependencies for Go ecosystem
- Maintain Envoy integration for external authorization

This change enables more flexible permission modeling through SpiceDB's
Google Zanzibar inspired relation-based system, supporting complex
hierarchical permissions that were difficult to express in Cedar.

Breaking change: Existing Cedar policies and Rust-based configuration
will no longer work and need to be migrated to SpiceDB schema.

1 files changed, 51 insertions, 0 deletions

diff --git a/vendor/github.com/authzed/grpcutil/reflection.go b/vendor/github.com/authzed/grpcutil/reflection.go
new file mode 100644
index 00000000..092b5680
--- /dev/null
+++ b/vendor/github.com/authzed/grpcutil/reflection.go
@@ -0,0 +1,51 @@
+package grpcutil
+
+import (
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/reflection"
+	rpbv1 "google.golang.org/grpc/reflection/grpc_reflection_v1"
+	"google.golang.org/grpc/reflection/grpc_reflection_v1alpha"
+)
+
+// NewAuthlessReflectionInterceptor creates a proxy GRPCServer which automatically converts
+// ServerReflectionServer instances to ones that skip grpc auth middleware.
+//
+// change:
+// reflection.Register(srv)
+// to:
+// reflection.Register(grpcutil.NewAuthlessReflectionInterceptor(srv))
+func NewAuthlessReflectionInterceptor(srv reflection.GRPCServer) reflection.GRPCServer {
+	return interceptingRegistrar{srv}
+}
+
+type interceptingRegistrar struct {
+	delegate reflection.GRPCServer
+}
+
+func (ir interceptingRegistrar) GetServiceInfo() map[string]grpc.ServiceInfo {
+	return ir.delegate.GetServiceInfo()
+}
+
+func (ir interceptingRegistrar) RegisterService(desc *grpc.ServiceDesc, impl interface{}) {
+	reflectionSrvv1, ok := impl.(rpbv1.ServerReflectionServer)
+	if ok {
+		ir.delegate.RegisterService(desc, &authlessReflectionV1{ServerReflectionServer: reflectionSrvv1})
+	}
+
+	reflectionSrvv1alpha, ok := impl.(grpc_reflection_v1alpha.ServerReflectionServer)
+	if ok {
+		ir.delegate.RegisterService(desc, &authlessReflectionV1Alpha{ServerReflectionServer: reflectionSrvv1alpha})
+	}
+}
+
+type authlessReflectionV1 struct {
+	IgnoreAuthMixin
+
+	rpbv1.ServerReflectionServer
+}
+
+type authlessReflectionV1Alpha struct {
+	IgnoreAuthMixin
+
+	grpc_reflection_v1alpha.ServerReflectionServer
+}