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, 40 deletions

diff --git a/vendor/rustix/src/backend/libc/rand/mod.rs b/vendor/rustix/src/backend/libc/rand/mod.rs
deleted file mode 100644
index 1e0181a9..00000000
--- a/vendor/rustix/src/backend/libc/rand/mod.rs
+++ /dev/null
@@ -1,2 +0,0 @@
-pub(crate) mod syscalls;
-pub(crate) mod types;
diff --git a/vendor/rustix/src/backend/libc/rand/syscalls.rs b/vendor/rustix/src/backend/libc/rand/syscalls.rs
deleted file mode 100644
index ce17c6aa..00000000
--- a/vendor/rustix/src/backend/libc/rand/syscalls.rs
+++ /dev/null
@@ -1,14 +0,0 @@
-//! libc syscalls supporting `rustix::rand`.
-
-#[cfg(linux_kernel)]
-use {crate::backend::c, crate::backend::conv::ret_usize, crate::io, crate::rand::GetRandomFlags};
-
-#[cfg(linux_kernel)]
-pub(crate) unsafe fn getrandom(buf: (*mut u8, usize), flags: GetRandomFlags) -> io::Result<usize> {
-    // `getrandom` wasn't supported in glibc until 2.25.
-    weak_or_syscall! {
-        fn getrandom(buf: *mut c::c_void, buflen: c::size_t, flags: c::c_uint) via SYS_getrandom -> c::ssize_t
-    }
-
-    ret_usize(getrandom(buf.0.cast(), buf.1, flags.bits()))
-}
diff --git a/vendor/rustix/src/backend/libc/rand/types.rs b/vendor/rustix/src/backend/libc/rand/types.rs
deleted file mode 100644
index 46690b57..00000000
--- a/vendor/rustix/src/backend/libc/rand/types.rs
+++ /dev/null
@@ -1,24 +0,0 @@
-#[cfg(linux_kernel)]
-use crate::backend::c;
-#[cfg(linux_kernel)]
-use bitflags::bitflags;
-
-#[cfg(linux_kernel)]
-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 = c::GRND_RANDOM;
-        /// `GRND_NONBLOCK`
-        const NONBLOCK = c::GRND_NONBLOCK;
-        /// `GRND_INSECURE`
-        const INSECURE = c::GRND_INSECURE;
-
-        /// <https://docs.rs/bitflags/*/bitflags/#externally-defined-flags>
-        const _ = !0;
-    }
-}