refactor: mover apps TUI de fn_operations/ a apps/

Separa aplicaciones ejecutables (docker_tui, pipeline_launcher) de la
librería fn_operations. La carpeta apps/ contiene módulos Go independientes,
fn_operations/ queda como librería pura de models/store/operations.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/docker_tui/views/keys.go

@@ -0,0 +1,14 @@
+package views
+
+// Navigation key constants.
+const (
+	KeyQuit = "ctrl+c"
+	KeyEsc  = "esc"
+	KeyBack = "0"
+	KeyTab  = "tab"
+)
+
+// IsBack returns true if the key should trigger back navigation.
+func IsBack(key string) bool {
+	return key == KeyEsc || key == KeyBack
+}