feat(app): add maestro tests, download progress, and task hierarchy

Add Maestro E2E test flows for app launch and sidebar interactions. Implement download progress tracking with speed/ETA display in file explorer. Extend task CLI with parent-child hierarchy, body content from stdin, and ancestor context in task show. Fix explorer sidebar gesture to allow horizontal scrolling while preserving close swipe. Replace hardcoded monospace font with Fonts.mono constant. Fix RefreshControl to only show spinner on manual pull-to-refresh.

packages/app/src/components/diff-viewer.tsx

@@ -2,6 +2,7 @@ import React from "react";
 import { View, Text } from "react-native";
 import { ScrollView } from "react-native-gesture-handler";
 import { StyleSheet } from "react-native-unistyles";
+import { Fonts } from "@/constants/theme";
 import type { DiffLine } from "@/utils/tool-call-parsers";
 
 interface DiffViewerProps {
@@ -80,7 +81,7 @@ const styles = StyleSheet.create((theme) => ({
     paddingVertical: theme.spacing[1],
   },
   lineText: {
-    fontFamily: "monospace",
+    fontFamily: Fonts.mono,
     fontSize: theme.fontSize.xs,
     color: theme.colors.foreground,
   },