app: add code for macOS and Windows apps under 'app' (#12933)

* app: add code for macOS and Windows apps under 'app'

* app: add readme

* app: windows and linux only for now

* ci: fix ui CI validation

---------

Co-authored-by: jmorganca <jmorganca@gmail.com>

app/format/field_test.go

@@ -0,0 +1,34 @@
+//go:build windows || darwin
+
+package format
+
+import "testing"
+
+func TestKebabCase(t *testing.T) {
+	tests := []struct {
+		input    string
+		expected string
+	}{
+		{"already-kebab-case", "already-kebab-case"},
+		{"simpleCamelCase", "simple-camel-case"},
+		{"PascalCase", "pascal-case"},
+		{"camelCaseWithNumber123", "camel-case-with-number123"},
+		{"APIResponse", "api-response"},
+		{"mixedCASE", "mixed-case"},
+		{"WithACRONYMS", "with-acronyms"},
+		{"ALLCAPS", "allcaps"},
+		{"camelCaseWITHMixedACRONYMS", "camel-case-with-mixed-acronyms"},
+		{"numbers123in456string", "numbers123in456string"},
+		{"5", "5"},
+		{"S", "s"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.input, func(t *testing.T) {
+			result := KebabCase(tt.input)
+			if result != tt.expected {
+				t.Errorf("toKebabCase(%q) = %q, want %q", tt.input, result, tt.expected)
+			}
+		})
+	}
+}