refactor(workspace): enforce layered crate boundaries

apps/aether-gateway/src/execution_runtime/constants.rs

@@ -1,3 +1,5 @@
-pub(crate) const MAX_ERROR_BODY_BYTES: usize = 16_384;
-pub(crate) const MAX_STREAM_PREFETCH_FRAMES: usize = 5;
-pub(crate) const MAX_STREAM_PREFETCH_BYTES: usize = 16_384;
+//! Compatibility facade for execution resource limits.
+
+pub(crate) use aether_gateway_execution::{
+    MAX_ERROR_BODY_BYTES, MAX_STREAM_PREFETCH_BYTES, MAX_STREAM_PREFETCH_FRAMES,
+};

apps/aether-gateway/src/execution_runtime/ndjson.rs

@@ -1,3 +1,5 @@
+//! Compatibility facade for execution stream framing.
+
 use std::io::Error as IoError;
 
 use aether_contracts::StreamFrame;
@@ -6,36 +8,10 @@ use axum::body::Bytes;
 use crate::GatewayError;
 
 pub(crate) fn encode_stream_frame_ndjson(frame: &StreamFrame) -> Result<Bytes, IoError> {
-    let mut raw = serde_json::to_vec(frame).map_err(|err| IoError::other(err.to_string()))?;
-    raw.push(b'\n');
-    Ok(Bytes::from(raw))
+    aether_gateway_execution::stream::encode_stream_frame_ndjson(frame)
 }
 
 pub(crate) fn decode_stream_frame_ndjson(line: &[u8]) -> Result<StreamFrame, GatewayError> {
-    serde_json::from_slice(line).map_err(|err| GatewayError::Internal(err.to_string()))
-}
-
-#[cfg(test)]
-mod tests {
-    use std::collections::BTreeMap;
-
-    use aether_contracts::{StreamFramePayload, StreamFrameType};
-
-    use super::{decode_stream_frame_ndjson, encode_stream_frame_ndjson};
-
-    #[test]
-    fn ndjson_round_trip_preserves_frame() {
-        let frame = aether_contracts::StreamFrame {
-            frame_type: StreamFrameType::Headers,
-            payload: StreamFramePayload::Headers {
-                status_code: 200,
-                headers: BTreeMap::from([("content-type".into(), "text/event-stream".into())]),
-            },
-        };
-
-        let raw = encode_stream_frame_ndjson(&frame).expect("frame should encode");
-        let decoded =
-            decode_stream_frame_ndjson(raw.trim_ascii_end()).expect("frame should decode");
-        assert_eq!(decoded, frame);
-    }
+    aether_gateway_execution::stream::decode_stream_frame_ndjson(line)
+        .map_err(|err| GatewayError::Internal(err.to_string()))
 }