refactor(ai-formats): group formats by provider

Move protocol/request/response format modules under provider-oriented formats modules and update registry, transport, and architecture paths.

crates/aether-ai-formats/src/protocol/mod.rs

@@ -1,7 +1,2 @@
 pub mod canonical;
-pub mod context;
-pub mod conversion;
-pub mod formats;
-pub mod matrix;
-pub mod registry;
 pub mod stream;