Fix linting issues: canonicalheader, embeddedstructfieldcheck, iotamixing, makezero, testableexamples, wastedassign, usetesting, tparallel, unconvert, intrange, iface

- canonicalheader: fix cacheTTL header value to canonical form
- embeddedstructfieldcheck: move embedded fields before regular fields in 4 structs
- iotamixing: split const blocks mixing iota with non-iota constants
- makezero: use make([]T, 0, n) instead of make([]T, n) before appending
- testableexamples: add missing Output: comment to ExampleOption_UnwrapOrZero
- wastedassign: remove wasted initial assignments in 4 locations
- usetesting: replace os.MkdirTemp/os.Setenv with t.TempDir/t.Setenv in tests
- tparallel: add t.Parallel() to 8 top-level test functions
- unconvert: remove 16 unnecessary type conversions
- intrange: convert 3 for loops to use integer range syntax
- iface: consolidate identical EditPrompter and Prompt interfaces via type alias

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

pkg/cmdutil/json_flags.go

@@ -52,7 +52,6 @@ func addTemplateFlag(f *pflag.FlagSet, shorthand string) {
 }
 
 func setupJsonFlags(cmd *cobra.Command, exportTarget *Exporter, fields []string) {
-
 	_ = cmd.RegisterFlagCompletionFunc("json", func(cmd *cobra.Command, args []string, toComplete string) ([]string, cobra.ShellCompDirective) {
 		var results []string
 		var prefix string
@@ -264,7 +263,7 @@ func (e *jsonExporter) exportData(v reflect.Value) interface{} {
 		}
 	case reflect.Slice:
 		a := make([]interface{}, v.Len())
-		for i := 0; i < v.Len(); i++ {
+		for i := range v.Len() {
 			a[i] = e.exportData(v.Index(i))
 		}
 		return a

pkg/cmdutil/json_flags_test.go

@@ -142,7 +142,6 @@ func TestAddJSONFlagsWithoutShorthand(t *testing.T) {
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-
 			cmd := &cobra.Command{Run: func(*cobra.Command, []string) {}}
 			tt.setFlags(cmd)