task_local context over context objects

- interner impls logically separate from API in orchid-base (default host interner still in base for testing)
- error reporting, logging, and a variety of other features passed down via context in extension, not yet in host to maintain library-ish profile, should consider options
- no global spawn mechanic, the host has a spawn function but extensions only get a stash for enqueuing async work in sync callbacks which is then explicitly, manually, and with strict order popped and awaited
- still deadlocks nondeterministically for some ungodly reason

orchid-api-traits/src/relations.rs

@@ -9,7 +9,7 @@ pub trait Request: fmt::Debug + Sized + 'static {
 	type Response: fmt::Debug + Coding + 'static;
 }
 
-pub async fn respond<R: Request>(_: &R, rep: R::Response) -> Vec<u8> { enc_vec(&rep).await }
+pub fn respond<R: Request>(_: &R, rep: R::Response) -> Vec<u8> { enc_vec(&rep) }
 
 pub trait Channel: 'static {
 	type Req: Coding + Sized + 'static;