Fix code formatting and update AGENT.md with correct lint command

- Fix gofmt formatting issues in internal/io/spinner_test.go and pkg/cmd/pipeline/create.go
- Update AGENT.md with correct golangci-lint command

Amp-Thread: https://ampcode.com/threads/T-69a131f0-814d-4d1d-b0fc-f7f61f34b1a6
Co-authored-by: Amp <amp@ampcode.com>

Author: sj26

AGENT.md

@@ -16,3 +16,4 @@ This project is the Buildkite CLI (`bk`)
 
 ## Notes
 - CI: https://buildkite.com/buildkite/buildkite-cli
+- Always format after changing code

internal/io/spinner_test.go

@@ -60,7 +60,7 @@ func TestSpinWhileTTYDetection(t *testing.T) {
 	// Test that TTY detection works as expected
 	// This test documents the behavior rather than forcing specific outcomes
 	isTTY := isatty.IsTerminal(os.Stdout.Fd())
-	
+
 	actionCalled := false
 	err := SpinWhile("TTY detection test", func() {
 		actionCalled = true

pkg/cmd/pipeline/create.go

@@ -6,11 +6,11 @@ import (
 
 	survey "github.com/AlecAivazis/survey/v2"
 	"github.com/MakeNowJust/heredoc"
+	bk_io "github.com/buildkite/cli/v3/internal/io"
 	"github.com/buildkite/cli/v3/pkg/cmd/factory"
 	buildkite "github.com/buildkite/go-buildkite/v4"
 	"github.com/charmbracelet/lipgloss"
 	"github.com/spf13/cobra"
-	bk_io "github.com/buildkite/cli/v3/internal/io"
 )
 
 func NewCmdPipelineCreate(f *factory.Factory) *cobra.Command {