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, 37 deletions

diff --git a/vendor/tower-layer/src/identity.rs b/vendor/tower-layer/src/identity.rs
deleted file mode 100644
index 5233a1d8..00000000
--- a/vendor/tower-layer/src/identity.rs
+++ /dev/null
@@ -1,37 +0,0 @@
-use super::Layer;
-use std::fmt;
-
-/// A no-op middleware.
-///
-/// When wrapping a [`Service`], the [`Identity`] layer returns the provided
-/// service without modifying it.
-///
-/// [`Service`]: https://docs.rs/tower-service/latest/tower_service/trait.Service.html
-#[derive(Default, Clone)]
-pub struct Identity {
-    _p: (),
-}
-
-impl Identity {
-    /// Create a new [`Identity`] value
-    pub const fn new() -> Identity {
-        Identity { _p: () }
-    }
-}
-
-/// Decorates a [`Service`], transforming either the request or the response.
-///
-/// [`Service`]: https://docs.rs/tower-service/latest/tower_service/trait.Service.html
-impl<S> Layer<S> for Identity {
-    type Service = S;
-
-    fn layer(&self, inner: S) -> Self::Service {
-        inner
-    }
-}
-
-impl fmt::Debug for Identity {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        f.debug_struct("Identity").finish()
-    }
-}