feat(protocol): freeze M4 native session RC6 contract

tools/native_conformance.swift

@@ -26,6 +26,8 @@ func evaluate(_ version: String, _ kind: String, _ input: String) -> String {
         guard (try? SessionRequest(
             clientDeviceId: values["client_device_id"] ?? "", deviceKeyId: values["device_key_id"] ?? "",
             poolId: values["pool_id"] ?? "", idempotencyKey: values["idempotency_key"] ?? "",
+            videoProfiles: [try! VideoProfile(codec: "h264", bitDepth: 8, chromaSubsampling: "4:2:0", colorSpace: "bt709-limited", transferFunction: "sdr")],
+            bitratePreference: try! BitratePreference(mode: "auto", targetKbps: nil),
             requestedDisplayMode: nil
         )) != nil else { return "invalid:required" }
         return "valid"
@@ -136,6 +138,9 @@ func classifyGatewayInput(_ encoded: String) -> String {
         let height = Int(body[6]) * 256 + Int(body[7])
         return width > 0 && height > 0 && x < width && y < height ? "valid" : "invalid:field"
     case 7: return body.count == 4 ? "valid" : "invalid:length"
+    case 8:
+        guard body.count == 8 else { return "invalid:length" }
+        return body[0] <= 15 && body[3] <= 3 ? "valid" : "invalid:field"
     default: return "invalid:kind"
     }
 }
@@ -156,6 +161,12 @@ func classifyGatewayFeedback(_ encoded: String) -> String {
         case 2:
             return validFECStatus(body) ? "valid" : "invalid:field"
         case 3: return body.isEmpty ? "valid" : "invalid:length"
+        case 4:
+            guard body.count == 24 else { return "invalid:length" }
+            return body[0...15].contains(where: { $0 != 0 }) && body[16...23].contains(where: { $0 != 0 }) ? "valid" : "invalid:field"
+        case 5:
+            guard body.count == 16 else { return "invalid:length" }
+            return body.contains(where: { $0 != 0 }) ? "valid" : "invalid:field"
         default: return "invalid:type"
         }
     }