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, 20 deletions

diff --git a/vendor/nonempty/README.md b/vendor/nonempty/README.md
deleted file mode 100644
index 0b18b605..00000000
--- a/vendor/nonempty/README.md
+++ /dev/null
@@ -1,20 +0,0 @@
-# Correct by Construction Non-Empty List
-
-This package exposes a type `NonEmpty<T>` with a data representation
-that guarantees non-emptiness statically:
-
-    struct NonEmpty<T>(T, Vec<T>)
-
-The library is meant to have an interface similar to `std::vec::Vec`:
-
-    use nonempty::NonEmpty;
-
-    let mut l = NonEmpty::new(42);
-
-    assert_eq!(l.first(), &42);
-
-    l.push(36);
-    l.push(58);
-
-    let v: Vec<i32> = l.into();
-    assert_eq!(v, vec![42, 36, 58]);