Implement domain and endpoint modules with capability management, message passing, and scheduling features

crates/domain/src/message.rs

@@ -0,0 +1,9 @@
+use types::bounded::CapSlot;
+
+pub const MAX_MESSAGE_WORDS: usize = 4;
+pub const MAX_CAP_TRANSFERS: usize = 4;
+
+pub struct Message {
+    words: [usize; MAX_MESSAGE_WORDS],
+    caps: [Option<CapSlot>; MAX_CAP_TRANSFERS],
+}