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.

3 files changed, 0 insertions, 37 deletions

diff --git a/vendor/rustix/src/backend/linux_raw/rand/mod.rs b/vendor/rustix/src/backend/linux_raw/rand/mod.rs
deleted file mode 100644
index 1e0181a9..00000000
--- a/vendor/rustix/src/backend/linux_raw/rand/mod.rs
+++ /dev/null
@@ -1,2 +0,0 @@
-pub(crate) mod syscalls;
-pub(crate) mod types;
diff --git a/vendor/rustix/src/backend/linux_raw/rand/syscalls.rs b/vendor/rustix/src/backend/linux_raw/rand/syscalls.rs
deleted file mode 100644
index acea3968..00000000
--- a/vendor/rustix/src/backend/linux_raw/rand/syscalls.rs
+++ /dev/null
@@ -1,15 +0,0 @@
-//! linux_raw syscalls supporting `rustix::rand`.
-//!
-//! # Safety
-//!
-//! See the `rustix::backend` module documentation for details.
-#![allow(unsafe_code, clippy::undocumented_unsafe_blocks)]
-
-use crate::backend::conv::{pass_usize, ret_usize};
-use crate::io;
-use crate::rand::GetRandomFlags;
-
-#[inline]
-pub(crate) unsafe fn getrandom(buf: (*mut u8, usize), flags: GetRandomFlags) -> io::Result<usize> {
-    ret_usize(syscall!(__NR_getrandom, buf.0, pass_usize(buf.1), flags))
-}
diff --git a/vendor/rustix/src/backend/linux_raw/rand/types.rs b/vendor/rustix/src/backend/linux_raw/rand/types.rs
deleted file mode 100644
index 9bc857fd..00000000
--- a/vendor/rustix/src/backend/linux_raw/rand/types.rs
+++ /dev/null
@@ -1,20 +0,0 @@
-use bitflags::bitflags;
-
-bitflags! {
-    /// `GRND_*` flags for use with [`getrandom`].
-    ///
-    /// [`getrandom`]: crate::rand::getrandom
-    #[repr(transparent)]
-    #[derive(Copy, Clone, Eq, PartialEq, Hash, Debug)]
-    pub struct GetRandomFlags: u32 {
-        /// `GRND_RANDOM`
-        const RANDOM = linux_raw_sys::general::GRND_RANDOM;
-        /// `GRND_NONBLOCK`
-        const NONBLOCK = linux_raw_sys::general::GRND_NONBLOCK;
-        /// `GRND_INSECURE`
-        const INSECURE = linux_raw_sys::general::GRND_INSECURE;
-
-        /// <https://docs.rs/bitflags/*/bitflags/#externally-defined-flags>
-        const _ = !0;
-    }
-}