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, 24 deletions

diff --git a/vendor/rustix/src/fs/openat2.rs b/vendor/rustix/src/fs/openat2.rs
deleted file mode 100644
index 0a0e1d16..00000000
--- a/vendor/rustix/src/fs/openat2.rs
+++ /dev/null
@@ -1,24 +0,0 @@
-use crate::fd::OwnedFd;
-use crate::{backend, io, path};
-use backend::fd::AsFd;
-use backend::fs::types::{Mode, OFlags, ResolveFlags};
-
-/// `openat2(dirfd, path, OpenHow { oflags, mode, resolve }, sizeof(OpenHow))`—
-/// Opens a file with more options.
-///
-/// # References
-///  - [Linux]
-///
-/// [Linux]: https://man7.org/linux/man-pages/man2/openat2.2.html
-#[inline]
-pub fn openat2<Fd: AsFd, P: path::Arg>(
-    dirfd: Fd,
-    path: P,
-    oflags: OFlags,
-    mode: Mode,
-    resolve: ResolveFlags,
-) -> io::Result<OwnedFd> {
-    path.into_with_c_str(|path| {
-        backend::fs::syscalls::openat2(dirfd.as_fd(), path, oflags, mode, resolve)
-    })
-}