Author or convert Fenix Android UI tests onto the ui/efficiency framework. Use this whenever the task involves writing a new efficiency UI test, converting/porting a legacy ui/ (robot-based) test onto the efficiency framework, or building what a test needs — page objects, selectors, navigation-graph nodes/edges, or BasePage primitives. Trigger even when the user doesn't name the framework: "convert this smoke test", "add a page object for the bookmarks screen", "wire up navigation to Settings", "write an efficiency test for X" all qualify. Do NOT use for edits to legacy robot-based tests that are staying on the old framework, or for non-Android test work.