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, 34 deletions

diff --git a/vendor/async-trait/src/parse.rs b/vendor/async-trait/src/parse.rs
deleted file mode 100644
index ebd25351..00000000
--- a/vendor/async-trait/src/parse.rs
+++ /dev/null
@@ -1,34 +0,0 @@
-use proc_macro2::Span;
-use syn::parse::{Error, Parse, ParseStream, Result};
-use syn::{Attribute, ItemImpl, ItemTrait, Token};
-
-pub enum Item {
-    Trait(ItemTrait),
-    Impl(ItemImpl),
-}
-
-impl Parse for Item {
-    fn parse(input: ParseStream) -> Result<Self> {
-        let attrs = input.call(Attribute::parse_outer)?;
-        let mut lookahead = input.lookahead1();
-        if lookahead.peek(Token![unsafe]) {
-            let ahead = input.fork();
-            ahead.parse::<Token![unsafe]>()?;
-            lookahead = ahead.lookahead1();
-        }
-        if lookahead.peek(Token![pub]) || lookahead.peek(Token![trait]) {
-            let mut item: ItemTrait = input.parse()?;
-            item.attrs = attrs;
-            Ok(Item::Trait(item))
-        } else if lookahead.peek(Token![impl]) {
-            let mut item: ItemImpl = input.parse()?;
-            if item.trait_.is_none() {
-                return Err(Error::new(Span::call_site(), "expected a trait impl"));
-            }
-            item.attrs = attrs;
-            Ok(Item::Impl(item))
-        } else {
-            Err(lookahead.error())
-        }
-    }
-}