Add watch stream protocol

proto/quixos/orch.proto

@@ -5,9 +5,11 @@ package quixos.orch;
 import "camino/api.proto";
 import "quixos/package.proto";
 import "quixos/refs.proto";
+import "quixos/runtime.proto";
 
 service OrchestratorRuntime {
   rpc InvokeFunction(InvokeFunctionRequest) returns (InvokeFunctionResponse);
+  rpc WatchFunction(WatchFunctionRequest) returns (stream WatchFunctionEvent);
   rpc ListPackageDescriptors(ListPackageDescriptorsRequest) returns (ListPackageDescriptorsResponse);
   rpc ListPackageRuntimes(ListPackageRuntimesRequest) returns (ListPackageRuntimesResponse);
   rpc ListActivations(ListActivationsRequest) returns (ListActivationsResponse);
@@ -28,6 +30,22 @@ message InvokeFunctionResponse {
   string error = 5;
 }
 
+message WatchFunctionRequest {
+  quixos.FunctionRef function = 1;
+  string object_id = 2;
+  map<string, camino.Value> input = 3;
+}
+
+message WatchFunctionEvent {
+  string invocation_id = 1;
+  Activation activation = 2;
+  string watch_id = 3;
+  camino.Value value = 4;
+  repeated quixos.runtime.DerivedDependency dependencies = 5;
+  string error = 6;
+  bool initial = 7;
+}
+
 message ListActivationsRequest {}
 
 message ListPackageDescriptorsRequest {}

proto/quixos/runtime.proto

@@ -8,6 +8,7 @@ import "quixos/refs.proto";
 service PackageRuntime {
   rpc Handshake(HandshakeRequest) returns (HandshakeResponse);
   rpc Invoke(InvokeRequest) returns (InvokeResponse);
+  rpc Watch(WatchRequest) returns (stream WatchEvent);
 }
 
 message HandshakeRequest {
@@ -33,3 +34,25 @@ message InvokeResponse {
   camino.Value result = 2;
   string error = 3;
 }
+
+message WatchRequest {
+  string invocation_id = 1;
+  quixos.FunctionRef function = 2;
+  string object_id = 3;
+  map<string, camino.Value> input = 4;
+}
+
+message DerivedDependency {
+  string kind = 1;
+  string object_id = 2;
+  string field_name = 3;
+  string source_field = 4;
+}
+
+message WatchEvent {
+  string watch_id = 1;
+  camino.Value value = 2;
+  repeated DerivedDependency dependencies = 3;
+  string error = 4;
+  bool initial = 5;
+}