feat: add managed accessibility helper with UIAutomator fallback

.env.example

@@ -22,6 +22,11 @@ ADB_PORT=5037
 # Keep the display awake, falling back to a wake lock or safe heartbeat when needed.
 # Set to false if Artemis is used with a personal device whose screen should time out.
 ARTEMIS_KEEP_DEVICE_AWAKE=true
+# UI hierarchy backend: auto (Accessibility Helper, UIAutomator2 fallback) | helper | uiautomator
+ARTEMIS_HIERARCHY_BACKEND=auto
+# Let tasks install / upgrade the Accessibility Helper APK on a device they hold.
+# Set to false on shared or personal phones: then only `artemis helper install` installs it.
+ARTEMIS_HELPER_AUTO_INSTALL=true
 
 # Artemis Execution Defaults (flash or pro)
 ARTEMIS_DEFAULT_PROFILE=flash