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, 15 deletions

diff --git a/vendor/petgraph/graph-example.dot b/vendor/petgraph/graph-example.dot
deleted file mode 100644
index f78ce41f..00000000
--- a/vendor/petgraph/graph-example.dot
+++ /dev/null
@@ -1,15 +0,0 @@
-digraph {
-rankdir = "LR";
-splines = true;
-
-    0 [label="petgraph"]
-    1 [label="fixedbitset"]
-    2 [label="quickcheck"]
-    3 [label="rand"]
-    4 [label="libc"]
-    0 -> 1
-    0 -> 2
-    2 -> 3
-    3 -> 4
-    2 -> 4
-}