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, 78 deletions

diff --git a/vendor/string_cache/README.md b/vendor/string_cache/README.md
deleted file mode 100644
index fdf4c0a3..00000000
--- a/vendor/string_cache/README.md
+++ /dev/null
@@ -1,78 +0,0 @@
-# string-cache
-
-[![Build Status](https://github.com/servo/string-cache/actions/workflows/ci.yml/badge.svg)](https://github.com/servo/string-cache/actions)
-
-[Documentation](https://docs.rs/string_cache/)
-
-A string interning library for Rust, developed as part of the [Servo](https://github.com/servo/servo) project.
-
-## Simple usage
-
-In `Cargo.toml`:
-
-```toml
-[dependencies]
-string_cache = "0.8"
-```
-
-In `lib.rs`:
-
-```rust
-extern crate string_cache;
-use string_cache::DefaultAtom as Atom;
-```
-
-## With static atoms
-
-In `Cargo.toml`:
-
-```toml
-[package]
-build = "build.rs"
-
-[dependencies]
-string_cache = "0.8"
-
-[build-dependencies]
-string_cache_codegen = "0.5"
-```
-
-In `build.rs`:
-
-```rust
-extern crate string_cache_codegen;
-
-use std::env;
-use std::path::Path;
-
-fn main() {
-    string_cache_codegen::AtomType::new("foo::FooAtom", "foo_atom!")
-        .atoms(&["foo", "bar"])
-        .write_to_file(&Path::new(&env::var("OUT_DIR").unwrap()).join("foo_atom.rs"))
-        .unwrap()
-}
-```
-
-In `lib.rs`:
-
-```rust
-extern crate string_cache;
-
-mod foo {
-    include!(concat!(env!("OUT_DIR"), "/foo_atom.rs"));
-}
-```
-
-The generated code will define a `FooAtom` type and a `foo_atom!` macro.
-The macro can be used in expression or patterns, with strings listed in `build.rs`.
-For example:
-
-```rust
-fn compute_something(input: &foo::FooAtom) -> u32 {
-    match *input {
-        foo_atom!("foo") => 1,
-        foo_atom!("bar") => 2,
-        _ => 3,
-    }
-}
-```