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, 62 deletions

diff --git a/vendor/errno/README.md b/vendor/errno/README.md
deleted file mode 100644
index 6a9a42c3..00000000
--- a/vendor/errno/README.md
+++ /dev/null
@@ -1,62 +0,0 @@
-# errno [![CI](https://github.com/lambda-fairy/rust-errno/actions/workflows/main.yml/badge.svg)](https://github.com/lambda-fairy/rust-errno/actions/workflows/main.yml) [![Cargo](https://img.shields.io/crates/v/errno.svg)](https://crates.io/crates/errno)
-
-Cross-platform interface to the [`errno`][errno] variable. Works on Rust 1.56 or newer.
-
-Documentation is available at <https://docs.rs/errno>.
-
-[errno]: https://en.wikipedia.org/wiki/Errno.h
-
-
-## Dependency
-
-Add to your `Cargo.toml`:
-
-```toml
-[dependencies]
-errno = "*"
-```
-
-
-## Comparison with `std::io::Error`
-
-The standard library provides [`Error::last_os_error`][last_os_error] which fetches `errno` in the same way.
-
-This crate provides these extra features:
-
-- No heap allocations
-- Optional `#![no_std]` support
-- A `set_errno` function
-
-[last_os_error]: https://doc.rust-lang.org/std/io/struct.Error.html#method.last_os_error
-
-
-## Examples
-
-```rust
-extern crate errno;
-use errno::{Errno, errno, set_errno};
-
-// Get the current value of errno
-let e = errno();
-
-// Set the current value of errno
-set_errno(e);
-
-// Extract the error code as an i32
-let code = e.0;
-
-// Display a human-friendly error message
-println!("Error {}: {}", code, e);
-```
-
-
-## `#![no_std]`
-
-Enable `#![no_std]` support by disabling the default `std` feature:
-
-```toml
-[dependencies]
-errno = { version = "*", default-features = false }
-```
-
-The `Error` impl will be unavailable.