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, 31 deletions

diff --git a/vendor/zeroize/src/aarch64.rs b/vendor/zeroize/src/aarch64.rs
deleted file mode 100644
index e9e15654..00000000
--- a/vendor/zeroize/src/aarch64.rs
+++ /dev/null
@@ -1,31 +0,0 @@
-//! [`Zeroize`] impls for ARM64 SIMD registers.
-
-use crate::{atomic_fence, volatile_write, Zeroize};
-
-use core::arch::aarch64::*;
-
-macro_rules! impl_zeroize_for_simd_register {
-    ($($type:ty),* $(,)?) => {
-        $(
-            impl Zeroize for $type {
-                #[inline]
-                fn zeroize(&mut self) {
-                    volatile_write(self, unsafe { core::mem::zeroed() });
-                    atomic_fence();
-                }
-            }
-        )+
-    };
-}
-
-// TODO(tarcieri): other NEON register types?
-impl_zeroize_for_simd_register! {
-    uint8x8_t,
-    uint8x16_t,
-    uint16x4_t,
-    uint16x8_t,
-    uint32x2_t,
-    uint32x4_t,
-    uint64x1_t,
-    uint64x2_t,
-}