Add React Native mobile app for Makima (#3)

* [WIP] Heartbeat checkpoint - 2026-01-18 02:58:27 UTC

* feat(mobile): complete mobile app integration and verification

- Add ThemeColors type export to Colors.ts for type safety
- Export SUPABASE_URL from supabase.ts and use environment variables
- Update .env.example with correct default URLs
- Add comprehensive README.md with setup instructions

Verified:
- TypeScript compiles without errors
- App exports successfully for iOS and Android
- All screens accessible (login, dashboard, tasks, settings, task detail)
- Auth flow working with Zustand store and Supabase

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* Task completion checkpoint

---------

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

1 files changed, 58 insertions, 0 deletions

diff --git a/apps/mobile/app/(tabs)/_layout.tsx b/apps/mobile/app/(tabs)/_layout.tsx
new file mode 100644
index 0000000..96c1a2d
--- /dev/null
+++ b/apps/mobile/app/(tabs)/_layout.tsx
@@ -0,0 +1,58 @@
+import React from 'react';
+import { Tabs } from 'expo-router';
+import { useColorScheme } from 'react-native';
+import { Ionicons } from '@expo/vector-icons';
+import { Colors } from '../../constants/Colors';
+
+export default function TabsLayout() {
+  const colorScheme = useColorScheme() ?? 'light';
+  const colors = Colors[colorScheme];
+
+  return (
+    <Tabs
+      screenOptions={{
+        tabBarActiveTintColor: colors.tint,
+        tabBarInactiveTintColor: colors.tabIconDefault,
+        tabBarStyle: {
+          backgroundColor: colors.background,
+          borderTopColor: colors.border,
+        },
+        headerStyle: {
+          backgroundColor: colors.background,
+        },
+        headerTintColor: colors.text,
+        headerTitleStyle: {
+          fontWeight: '600',
+        },
+      }}
+    >
+      <Tabs.Screen
+        name="index"
+        options={{
+          title: 'Dashboard',
+          tabBarIcon: ({ color, size }) => (
+            <Ionicons name="home" size={size} color={color} />
+          ),
+        }}
+      />
+      <Tabs.Screen
+        name="tasks"
+        options={{
+          title: 'Tasks',
+          tabBarIcon: ({ color, size }) => (
+            <Ionicons name="list" size={size} color={color} />
+          ),
+        }}
+      />
+      <Tabs.Screen
+        name="settings"
+        options={{
+          title: 'Settings',
+          tabBarIcon: ({ color, size }) => (
+            <Ionicons name="settings-outline" size={size} color={color} />
+          ),
+        }}
+      />
+    </Tabs>
+  );
+}