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, 0 insertions, 60 deletions

diff --git a/vendor/ref-cast/src/layout.rs b/vendor/ref-cast/src/layout.rs
deleted file mode 100644
index 55f91f8c..00000000
--- a/vendor/ref-cast/src/layout.rs
+++ /dev/null
@@ -1,60 +0,0 @@
-use core::mem;
-
-#[doc(hidden)]
-pub struct Layout<T: ?Sized>(T);
-
-#[doc(hidden)]
-pub trait LayoutUnsized<T: ?Sized> {
-    const SIZE: usize = usize::MAX;
-    const ALIGN: usize = usize::MAX;
-}
-
-impl<T: ?Sized> LayoutUnsized<T> for Layout<T> {}
-
-impl<T> Layout<T> {
-    pub const SIZE: usize = mem::size_of::<T>();
-    pub const ALIGN: usize = mem::align_of::<T>();
-}
-
-#[doc(hidden)]
-#[inline]
-pub fn assert_layout<Outer: ?Sized, Inner: ?Sized>(
-    name: &'static str,
-    outer_size: usize,
-    inner_size: usize,
-    outer_align: usize,
-    inner_align: usize,
-) {
-    if outer_size != inner_size {
-        #[cfg(no_intrinsic_type_name)]
-        panic!(
-            "unexpected size in cast to {}: {} != {}",
-            name, outer_size, inner_size,
-        );
-        #[cfg(not(no_intrinsic_type_name))]
-        panic!(
-            "unexpected size in cast from {} to {}: {} != {}",
-            core::any::type_name::<Inner>(),
-            core::any::type_name::<Outer>(),
-            inner_size,
-            outer_size,
-        );
-    }
-    if outer_align != inner_align {
-        #[cfg(no_intrinsic_type_name)]
-        panic!(
-            "unexpected alignment in cast to {}: {} != {}",
-            name, outer_align, inner_align,
-        );
-        #[cfg(not(no_intrinsic_type_name))]
-        panic!(
-            "unexpected alignment in cast from {} to {}: {} != {}",
-            core::any::type_name::<Inner>(),
-            core::any::type_name::<Outer>(),
-            inner_align,
-            outer_align,
-        );
-    }
-    #[cfg(not(no_intrinsic_type_name))]
-    let _ = name;
-}