refactor(navigation): consolidate navigation with href helpers and extract push device hook

- Migrate all navigation calls from magic strings to centralized href helpers
- Extract inline device registration logic into useRegisterPushDevice hook
- Remove unused terms and privacy policy routes from profile stack
- Add hrefTradeDetail helper for trade detail navigation
- Restore routePayloadCache.stashSystemMessage for group request/invite handling
- Change desktop shell tab navigation from replace to push

app/(app)/(tabs)/_layout.tsx

@@ -1,6 +1,6 @@
 import { useMemo, useCallback } from 'react';
 import { Platform, Pressable, useWindowDimensions } from 'react-native';
-import { Tabs, usePathname } from 'expo-router';
+import { Tabs, usePathname, useRouter } from 'expo-router';
 import { MaterialCommunityIcons } from '@expo/vector-icons';
 import { useSafeAreaInsets } from 'react-native-safe-area-context';
 import type { PressableProps } from 'react-native';
@@ -8,6 +8,7 @@ import type { PressableProps } from 'react-native';
 import { useAppColors, shadows } from '../../../src/theme';
 import { BREAKPOINTS } from '../../../src/hooks';
 import { useHomeTabBarVisibilityStore, useTotalUnreadCount, useHomeTabPressStore } from '../../../src/stores';
+import { hrefHome } from '../../../src/navigation/hrefs';
 
 const TAB_BAR_HEIGHT = 56;
 const TAB_BAR_FLOATING_MARGIN = 12;
@@ -28,6 +29,7 @@ export default function TabsLayout() {
   const { width } = useWindowDimensions();
   const insets = useSafeAreaInsets();
   const pathname = usePathname();
+  const router = useRouter();
   const unreadCount = useTotalUnreadCount();
   const scrollHideTabBar = useHomeTabBarVisibilityStore((s) => s.bottomTabBarHiddenByScroll);
   const triggerHomeTabPress = useHomeTabPressStore((s) => s.triggerPress);
@@ -35,11 +37,18 @@ export default function TabsLayout() {
 
   const isHomeStackRoute = pathname === '/home' || pathname.startsWith('/home/');
 
-  const handleHomeTabPress = useCallback(() => {
-    if (pathname === '/home') {
-      triggerHomeTabPress();
-    }
-  }, [pathname, triggerHomeTabPress]);
+  const handleHomeTabPress = useCallback(
+    (e: { preventDefault: () => void }) => {
+      if (!isHomeStackRoute) return;
+      e.preventDefault();
+      if (pathname === '/home') {
+        triggerHomeTabPress();
+      } else {
+        router.navigate(hrefHome());
+      }
+    },
+    [isHomeStackRoute, pathname, triggerHomeTabPress, router]
+  );
 
   const tabBarStyle = useMemo(() => {
     if (hideTabBar) {

app/(app)/(tabs)/profile/_layout.tsx

@@ -17,8 +17,6 @@ export default function ProfileStackLayout() {
       <Stack.Screen name="blocked-users" />
       <Stack.Screen name="chat-settings" />
       <Stack.Screen name="about" />
-      <Stack.Screen name="terms" />
-      <Stack.Screen name="privacy" />
       <Stack.Screen name="verification" />
       <Stack.Screen name="data-storage" />
       <Stack.Screen name="privacy-settings" />

app/(app)/(tabs)/profile/privacy.tsx

@@ -1,5 +0,0 @@
-import { PrivacyPolicyScreen } from '../../../../src/screens/profile/PrivacyPolicyScreen';
-
-export default function PrivacyPolicyRoute() {
-  return <PrivacyPolicyScreen />;
-}

app/(app)/(tabs)/profile/terms.tsx

@@ -1,5 +0,0 @@
-import { TermsOfServiceScreen } from '../../../../src/screens/profile/TermsOfServiceScreen';
-
-export default function TermsOfServiceRoute() {
-  return <TermsOfServiceScreen />;
-}