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, 35 deletions

diff --git a/vendor/errno/src/sys.rs b/vendor/errno/src/sys.rs
deleted file mode 100644
index cc6fe8a8..00000000
--- a/vendor/errno/src/sys.rs
+++ /dev/null
@@ -1,35 +0,0 @@
-//! A default sys.rs for unrecognized targets.
-//!
-//! If lib.rs doesn't recognize the target, it defaults to using this file,
-//! which issues an explanatory compile error.
-
-// If there is no OS, there's no `errno` or equivalent defined.
-#[cfg(any(target_os = "unknown", target_os = "none"))]
-compile_error!("The target OS is \"unknown\" or \"none\", so it's unsupported by the errno crate.");
-
-// If there is an OS, support may be added.
-#[cfg(not(any(target_os = "unknown", target_os = "none")))]
-compile_error!("The target OS is not yet supported in the errno crate.");
-
-// The following define the functions of the normal implementations
-// so that the user doesn't see uninteresting errors after the
-// errors above.
-
-use crate::Errno;
-
-pub fn with_description<F, T>(_err: Errno, _callback: F) -> T
-where
-    F: FnOnce(Result<&str, Errno>) -> T,
-{
-    unreachable!()
-}
-
-pub const STRERROR_NAME: &str = "";
-
-pub fn errno() -> Errno {
-    unreachable!()
-}
-
-pub fn set_errno(_: Errno) {
-    unreachable!()
-}