feat(policy): add the TAIP-7 for field to Policy

types.go

@@ -112,6 +112,7 @@ type Policy struct {
 	Type                   string   `json:"@type"`
 	Context                any      `json:"@context,omitempty"`
 	From                   string   `json:"from,omitempty"`
+	For                    string   `json:"for,omitempty"`
 	FromAgent              string   `json:"fromAgent,omitempty"`
 	FromRole               string   `json:"fromRole,omitempty"`
 	AboutParty             string   `json:"aboutParty,omitempty"`

types_test.go

@@ -156,6 +156,28 @@ func TestPolicy_FromFieldRoundTrip(t *testing.T) {
 	}
 }
 
+func TestPolicy_ForFieldRoundTrip(t *testing.T) {
+	in := Policy{
+		Type: "RequireRelationshipConfirmation",
+		From: "did:pkh:eip155:1:0xabc",
+		For:  "did:web:originator.vasp.example",
+	}
+	data, err := json.Marshal(in)
+	if err != nil {
+		t.Fatalf("marshal: %v", err)
+	}
+	if !bytes.Contains(data, []byte(`"for":"did:web:originator.vasp.example"`)) {
+		t.Fatalf("missing for in JSON: %s", string(data))
+	}
+	var out Policy
+	if err := json.Unmarshal(data, &out); err != nil {
+		t.Fatalf("unmarshal: %v", err)
+	}
+	if out.For != in.For {
+		t.Errorf("For = %q, want %q", out.For, in.For)
+	}
+}
+
 func TestTransactionConstraints_JSONRoundTrip(t *testing.T) {
 	tc := TransactionConstraints{
 		Purposes:         []string{"BEXP", "SUPP"},