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/cmd/factory/default_test.go

@@ -675,7 +675,7 @@ func TestSSOURL(t *testing.T) {
 
 	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		if sso := r.URL.Query().Get("sso"); sso != "" {
-			w.Header().Set("X-GitHub-SSO", sso)
+			w.Header().Set("X-Github-Sso", sso)
 		}
 		w.WriteHeader(http.StatusNoContent)
 	}))
@@ -734,7 +734,7 @@ func TestPlainHttpClient(t *testing.T) {
 
 	assert.Equal(t, 204, res.StatusCode)
 	assert.Equal(t, []string{"GitHub CLI v1.2.3"}, receivedHeaders.Values("User-Agent"))
-	assert.Equal(t, []string{"2022-11-28"}, receivedHeaders.Values("X-GitHub-Api-Version"))
+	assert.Equal(t, []string{"2022-11-28"}, receivedHeaders.Values("X-Github-Api-Version"))
 	assert.Nil(t, receivedHeaders.Values("Authorization"))
 	assert.Nil(t, receivedHeaders.Values("Content-Type"))
 	assert.Nil(t, receivedHeaders.Values("Accept"))