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, 38 deletions

diff --git a/vendor/digest/src/dev/rng.rs b/vendor/digest/src/dev/rng.rs
deleted file mode 100644
index d34a1cf3..00000000
--- a/vendor/digest/src/dev/rng.rs
+++ /dev/null
@@ -1,38 +0,0 @@
-//! Xorshift RNG used for tests. Based on the `rand_xorshift` crate.
-use core::num::Wrapping;
-
-/// Initial RNG state used in tests.
-// chosen by fair dice roll. guaranteed to be random.
-pub(crate) const RNG: XorShiftRng = XorShiftRng {
-    x: Wrapping(0x0787_3B4A),
-    y: Wrapping(0xFAAB_8FFE),
-    z: Wrapping(0x1745_980F),
-    w: Wrapping(0xB0AD_B4F3),
-};
-
-/// Xorshift RNG instance/
-pub(crate) struct XorShiftRng {
-    x: Wrapping<u32>,
-    y: Wrapping<u32>,
-    z: Wrapping<u32>,
-    w: Wrapping<u32>,
-}
-
-impl XorShiftRng {
-    pub(crate) fn fill(&mut self, buf: &mut [u8; 1024]) {
-        for chunk in buf.chunks_exact_mut(4) {
-            chunk.copy_from_slice(&self.next_u32().to_le_bytes());
-        }
-    }
-
-    fn next_u32(&mut self) -> u32 {
-        let x = self.x;
-        let t = x ^ (x << 11);
-        self.x = self.y;
-        self.y = self.z;
-        self.z = self.w;
-        let w = self.w;
-        self.w = w ^ (w >> 19) ^ (t ^ (t >> 8));
-        self.w.0
-    }
-}