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, 73 deletions

diff --git a/vendor/hyper/src/common/watch.rs b/vendor/hyper/src/common/watch.rs
deleted file mode 100644
index ba17d551..00000000
--- a/vendor/hyper/src/common/watch.rs
+++ /dev/null
@@ -1,73 +0,0 @@
-//! An SPSC broadcast channel.
-//!
-//! - The value can only be a `usize`.
-//! - The consumer is only notified if the value is different.
-//! - The value `0` is reserved for closed.
-
-use futures_util::task::AtomicWaker;
-use std::sync::{
-    atomic::{AtomicUsize, Ordering},
-    Arc,
-};
-use std::task;
-
-type Value = usize;
-
-pub(crate) const CLOSED: usize = 0;
-
-pub(crate) fn channel(initial: Value) -> (Sender, Receiver) {
-    debug_assert!(
-        initial != CLOSED,
-        "watch::channel initial state of 0 is reserved"
-    );
-
-    let shared = Arc::new(Shared {
-        value: AtomicUsize::new(initial),
-        waker: AtomicWaker::new(),
-    });
-
-    (
-        Sender {
-            shared: shared.clone(),
-        },
-        Receiver { shared },
-    )
-}
-
-pub(crate) struct Sender {
-    shared: Arc<Shared>,
-}
-
-pub(crate) struct Receiver {
-    shared: Arc<Shared>,
-}
-
-struct Shared {
-    value: AtomicUsize,
-    waker: AtomicWaker,
-}
-
-impl Sender {
-    pub(crate) fn send(&mut self, value: Value) {
-        if self.shared.value.swap(value, Ordering::SeqCst) != value {
-            self.shared.waker.wake();
-        }
-    }
-}
-
-impl Drop for Sender {
-    fn drop(&mut self) {
-        self.send(CLOSED);
-    }
-}
-
-impl Receiver {
-    pub(crate) fn load(&mut self, cx: &mut task::Context<'_>) -> Value {
-        self.shared.waker.register(cx.waker());
-        self.shared.value.load(Ordering::SeqCst)
-    }
-
-    pub(crate) fn peek(&self) -> Value {
-        self.shared.value.load(Ordering::Relaxed)
-    }
-}