fix(account): register through the Build registration API

AGENTS.md

@@ -420,7 +420,7 @@ agent with email/web access) to finish.
 
 ```bash
 band account register --phone +15555550100 --email [email protected] --first-name Jane --last-name Doe --accept-tos
-# → registration submitted (POST /v1/express/registration)
+# → registration submitted (POST /v1/build/registrations)
 
 band account send-code --phone +15555550100 --email [email protected] --delivery-channel sms   # or "voice"
 # → verification code sent. Choosing "sms" IS the customer's consent to

cmd/account/golden_test.go

@@ -22,7 +22,7 @@ func TestRegisterPlainOutput(t *testing.T) {
 		"links": []interface{}{},
 		"data": map[string]interface{}{
 			"message":        "Onboarding request received successfully",
-			"status":         "USER_CREATION_PENDING",
+			"status":         "USER_CREATION_INITIATED",
 			"registrationId": "reg-123",
 		},
 		"errors": []interface{}{},
@@ -47,13 +47,13 @@ func TestRegisterPlainOutput(t *testing.T) {
 		}
 	})
 
-	want := "{\n  \"message\": \"Onboarding request received successfully\",\n  \"registrationId\": \"reg-123\",\n  \"status\": \"USER_CREATION_PENDING\"\n}\n"
+	want := "{\n  \"message\": \"Onboarding request received successfully\",\n  \"registrationId\": \"reg-123\",\n  \"status\": \"USER_CREATION_INITIATED\"\n}\n"
 	if out != want {
 		t.Fatalf("golden mismatch:\n got: %q\nwant: %q", out, want)
 	}
 
-	if fake.PostPath != "/registration" {
-		t.Errorf("PostPath = %q, want %q", fake.PostPath, "/registration")
+	if fake.PostPath != "/registrations" {
+		t.Errorf("PostPath = %q, want %q", fake.PostPath, "/registrations")
 	}
 	body, ok := fake.PostBody.(map[string]interface{})
 	if !ok {
@@ -101,8 +101,8 @@ func TestSendCodePlainOutput(t *testing.T) {
 		t.Fatalf("golden mismatch:\n got: %q\nwant: %q", out, want)
 	}
 
-	if fake.PostPath != "/registration/code" {
-		t.Errorf("PostPath = %q, want %q", fake.PostPath, "/registration/code")
+	if fake.PostPath != "/registrations/code" {
+		t.Errorf("PostPath = %q, want %q", fake.PostPath, "/registrations/code")
 	}
 	body, ok := fake.PostBody.(map[string]interface{})
 	if !ok {
@@ -145,8 +145,8 @@ func TestVerifyPlainOutput(t *testing.T) {
 		t.Fatalf("golden mismatch:\n got: %q\nwant: %q", out, want)
 	}
 
-	if fake.PostPath != "/registration/code/verify" {
-		t.Errorf("PostPath = %q, want %q", fake.PostPath, "/registration/code/verify")
+	if fake.PostPath != "/registrations/code/verify" {
+		t.Errorf("PostPath = %q, want %q", fake.PostPath, "/registrations/code/verify")
 	}
 	body, ok := fake.PostBody.(map[string]interface{})
 	if !ok {

cmd/account/register.go

@@ -110,7 +110,7 @@ func runRegister(cmd *cobra.Command, args []string) error {
 	}
 
 	var result interface{}
-	if err := client.Post(cmd.Context(), "/registration", reqBody, &result); err != nil {
+	if err := client.Post(cmd.Context(), "/registrations", reqBody, &result); err != nil {
 		return fmt.Errorf("registering account: %w", err)
 	}
 

cmd/account/send_code.go

@@ -71,7 +71,7 @@ func runSendCode(cmd *cobra.Command, args []string) error {
 	}
 
 	var result interface{}
-	if err := client.Post(cmd.Context(), "/registration/code", reqBody, &result); err != nil {
+	if err := client.Post(cmd.Context(), "/registrations/code", reqBody, &result); err != nil {
 		return fmt.Errorf("sending verification code: %w", err)
 	}
 

cmd/account/verify.go

@@ -53,7 +53,7 @@ func runVerify(cmd *cobra.Command, args []string) error {
 	}
 
 	var result interface{}
-	if err := client.Post(cmd.Context(), "/registration/code/verify", reqBody, &result); err != nil {
+	if err := client.Post(cmd.Context(), "/registrations/code/verify", reqBody, &result); err != nil {
 		return fmt.Errorf("verifying phone number: %w", err)
 	}
 

internal/cmdutil/helpers.go

@@ -78,7 +78,7 @@ func apiHostForEnvironment(env string) string {
 
 // RegistrationHost returns the Build registration API base URL, honoring BW_API_URL like every other client in this file.
 func RegistrationHost() string {
-	return apiHostForEnvironment("") + "/v1/express"
+	return apiHostForEnvironment("") + "/v1/build"
 }
 
 // voiceHostForEnvironment maps an environment name to its Voice API host.

internal/cmdutil/helpers_test.go

@@ -133,6 +133,20 @@ func TestMessagingHost_BW_MESSAGING_URL_TrailingSlash(t *testing.T) {
 	}
 }
 
+func TestRegistrationHost(t *testing.T) {
+	t.Setenv("BW_API_URL", "")
+	if got := RegistrationHost(); got != "https://api.bandwidth.com/v1/build" {
+		t.Errorf("RegistrationHost() = %q, want https://api.bandwidth.com/v1/build", got)
+	}
+}
+
+func TestRegistrationHost_BW_API_URL(t *testing.T) {
+	t.Setenv("BW_API_URL", "https://custom.example.com/")
+	if got := RegistrationHost(); got != "https://custom.example.com/v1/build" {
+		t.Errorf("RegistrationHost() with BW_API_URL = %q, want https://custom.example.com/v1/build", got)
+	}
+}
+
 func TestResolveEnvironment(t *testing.T) {
 	t.Run("no override returns profile env", func(t *testing.T) {
 		EnvironmentOverride = ""