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, 56 deletions

diff --git a/vendor/rustversion/src/error.rs b/vendor/rustversion/src/error.rs
deleted file mode 100644
index a99625b4..00000000
--- a/vendor/rustversion/src/error.rs
+++ /dev/null
@@ -1,56 +0,0 @@
-use proc_macro::{Delimiter, Group, Ident, Literal, Punct, Spacing, Span, TokenStream, TokenTree};
-use std::fmt::Display;
-use std::iter::FromIterator;
-
-pub type Result<T, E = Error> = std::result::Result<T, E>;
-
-pub struct Error {
-    begin: Span,
-    end: Span,
-    msg: String,
-}
-
-impl Error {
-    pub fn new(span: Span, msg: impl Display) -> Self {
-        Self::new2(span, span, msg)
-    }
-
-    pub fn new2(begin: Span, end: Span, msg: impl Display) -> Self {
-        Error {
-            begin,
-            end,
-            msg: msg.to_string(),
-        }
-    }
-
-    pub fn group(group: Group, msg: impl Display) -> Self {
-        let mut iter = group.stream().into_iter();
-        let delimiter = group.span();
-        let begin = iter.next().map_or(delimiter, |t| t.span());
-        let end = iter.last().map_or(begin, |t| t.span());
-        Self::new2(begin, end, msg)
-    }
-
-    pub fn into_compile_error(self) -> TokenStream {
-        // compile_error! { $msg }
-        TokenStream::from_iter(vec![
-            TokenTree::Ident(Ident::new("compile_error", self.begin)),
-            TokenTree::Punct({
-                let mut punct = Punct::new('!', Spacing::Alone);
-                punct.set_span(self.begin);
-                punct
-            }),
-            TokenTree::Group({
-                let mut group = Group::new(Delimiter::Brace, {
-                    TokenStream::from_iter(vec![TokenTree::Literal({
-                        let mut string = Literal::string(&self.msg);
-                        string.set_span(self.end);
-                        string
-                    })])
-                });
-                group.set_span(self.end);
-                group
-            }),
-        ])
-    }
-}