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, 34 deletions

diff --git a/vendor/writeable/tests/writeable.rs b/vendor/writeable/tests/writeable.rs
deleted file mode 100644
index b48310e8..00000000
--- a/vendor/writeable/tests/writeable.rs
+++ /dev/null
@@ -1,34 +0,0 @@
-// This file is part of ICU4X. For terms of use, please see the file
-// called LICENSE at the top level of the ICU4X source tree
-// (online at: https://github.com/unicode-org/icu4x/blob/main/LICENSE ).
-
-use std::fmt;
-use writeable::assert_writeable_eq;
-use writeable::LengthHint;
-use writeable::Writeable;
-
-/// A sample type implementing Writeable
-struct WriteableMessage<'s> {
-    message: &'s str,
-}
-
-impl Writeable for WriteableMessage<'_> {
-    fn write_to<W: fmt::Write + ?Sized>(&self, sink: &mut W) -> fmt::Result {
-        sink.write_str(self.message)
-    }
-
-    fn writeable_length_hint(&self) -> LengthHint {
-        LengthHint::exact(self.message.len())
-    }
-}
-
-writeable::impl_display_with_writeable!(WriteableMessage<'_>);
-
-#[test]
-fn test_basic() {
-    let input_string = "hello world";
-    let message = WriteableMessage {
-        message: input_string,
-    };
-    assert_writeable_eq!(&message, input_string);
-}