feat(Materials): add new materials navigation and href functions

- Introduced href functions for accessing materials, including hrefMaterials, hrefMaterialSubject, and hrefMaterialDetail.
- Updated AppsScreen to include a new entry for materials, enhancing the app's educational resources section.
- Exported material types in index.ts to support the new materials functionality.

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

@@ -0,0 +1,11 @@
+import { Stack } from 'expo-router';
+
+export default function MaterialsStackLayout() {
+  return (
+    <Stack screenOptions={{ headerShown: false }}>
+      <Stack.Screen name="index" />
+      <Stack.Screen name="subject" />
+      <Stack.Screen name="detail" />
+    </Stack>
+  );
+}

app/(app)/(tabs)/apps/materials/detail.tsx

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

app/(app)/(tabs)/apps/materials/index.tsx

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

app/(app)/(tabs)/apps/materials/subject.tsx

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