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, 39 deletions

diff --git a/vendor/rustix/src/bitcast.rs b/vendor/rustix/src/bitcast.rs
deleted file mode 100644
index db17c7cb..00000000
--- a/vendor/rustix/src/bitcast.rs
+++ /dev/null
@@ -1,39 +0,0 @@
-//! The `bitcast` and `bitflags_bits` macros.
-
-#![allow(unused_macros)]
-
-// Ensure that the source and destination types are both primitive integer
-// types and the same size, and then bitcast.
-macro_rules! bitcast {
-    ($x:expr) => {{
-        if false {
-            // Ensure the source and destinations are primitive integer types.
-            let _ = !$x;
-            let _ = $x as u8;
-            0
-        } else if false {
-            // Ensure that the source and destinations are the same size.
-            #[allow(
-                unsafe_code,
-                unused_unsafe,
-                clippy::useless_transmute,
-                clippy::missing_transmute_annotations
-            )]
-            // SAFETY: This code is under an `if false`.
-            unsafe {
-                ::core::mem::transmute($x)
-            }
-        } else {
-            // Do the conversion.
-            $x as _
-        }
-    }};
-}
-
-/// Return a [`bitcast`] of the value of `$x.bits()`, where `$x` is a
-/// `bitflags` type.
-macro_rules! bitflags_bits {
-    ($x:expr) => {{
-        bitcast!($x.bits())
-    }};
-}