O-4: the call that reads a sent object

Builds: design 47 G §347, §407

Claude-Session: https://claude.ai/code/session_01JG73KEq4zoDfM9WtYpcQgZ

go/buscalls/buscalls.go

@@ -28,6 +28,10 @@ const (
 	ObjectsDelete = "mesh/objects.delete"
 	ObjectsInfo   = "mesh/objects.info"
 	ObjectsWatch  = "mesh/objects.watch"
+	// ObjectsSentGet reads an object of a sender's store of sent objects by the reference a reply or an event carried
+	// (design 47 G §347, §407), served under the standing grant the grants part derives from the manifests; the answer is
+	// ObjectData.
+	ObjectsSentGet = "mesh/objects.sent-get"
 
 	StreamRead = "mesh/stream.read"
 	StreamFill = "mesh/stream.fill"
@@ -103,6 +107,15 @@ type ObjectInfo struct {
 	Deleted     bool      `json:"deleted,omitempty"`
 }
 
+// ObjectsSentGetRequest names one sent object by the reference that carried it (stateobjects.Ref's fields, which this
+// package does not import): the sender's store, the object's name, and its size and digest, which the reader checks.
+type ObjectsSentGetRequest struct {
+	Store  string `json:"store"`
+	Object string `json:"object"`
+	Size   int64  `json:"size"`
+	Digest string `json:"sha256"`
+}
+
 // ObjectData is get's answer: the object's info and its bytes.
 type ObjectData struct {
 	Info ObjectInfo `json:"info"`

go/packages_list_test.go

@@ -311,6 +311,12 @@ func TestMeshSDKHoldsOnlyWhatEveryModuleShares(t *testing.T) {
 			t.Errorf("%s: unwrapped %s, %q, %v; want %s, %q, %v", c.name, answer, said, ok, c.answer, c.said, c.ok)
 		}
 	}
+	// design 47 G §347: a sent object is asked by its reference's fields.
+	sentAsk := buscalls.ObjectsSentGetRequest{Store: "m_sent-objects", Object: "o", Size: 3 << 20, Digest: strings.Repeat("b", 64)}
+	if raw, err := json.Marshal(sentAsk); err != nil || buscalls.ObjectsSentGet != "mesh/objects.sent-get" ||
+		string(raw) != `{"store":"m_sent-objects","object":"o","size":3145728,"sha256":"`+strings.Repeat("b", 64)+`"}` {
+		t.Errorf("the sent-get request is %s, %v", raw, err)
+	}
 	// 1966/AC5: an apply naming the tool call it serves, and its answer with the state behind, round-trip.
 	for _, c := range []struct {
 		name     string