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, 384 insertions, 0 deletions

diff --git a/apps/mobile/app/(auth)/login.tsx b/apps/mobile/app/(auth)/login.tsx
new file mode 100644
index 0000000..7e0f14f
--- /dev/null
+++ b/apps/mobile/app/(auth)/login.tsx
@@ -0,0 +1,384 @@
+import React, { useState, useCallback, useRef } from 'react';
+import {
+  View,
+  Text,
+  TextInput,
+  TouchableOpacity,
+  StyleSheet,
+  KeyboardAvoidingView,
+  Platform,
+  ScrollView,
+  ActivityIndicator,
+  Linking,
+  type TextInput as TextInputType,
+} from 'react-native';
+import { useColorScheme } from 'react-native';
+import { router } from 'expo-router';
+import { Colors } from '../../constants/Colors';
+import { useAuthStore } from '../../stores/authStore';
+import { config } from '../../lib/config';
+
+/**
+ * Email validation regex
+ */
+const EMAIL_REGEX = /^[^\s@]+@[^\s@]+\.[^\s@]+$/;
+
+/**
+ * Login screen component
+ * Handles user authentication with email and password
+ */
+export default function LoginScreen() {
+  const colorScheme = useColorScheme() ?? 'dark';
+  const colors = Colors[colorScheme];
+
+  // Form state
+  const [email, setEmail] = useState('');
+  const [password, setPassword] = useState('');
+  const [emailError, setEmailError] = useState<string | null>(null);
+  const [passwordError, setPasswordError] = useState<string | null>(null);
+
+  // Refs for input focus
+  const passwordInputRef = useRef<TextInputType>(null);
+
+  // Auth store
+  const signIn = useAuthStore((state) => state.signIn);
+  const isLoading = useAuthStore((state) => state.isLoading);
+  const authError = useAuthStore((state) => state.error);
+  const clearError = useAuthStore((state) => state.clearError);
+
+  /**
+   * Validate email format
+   */
+  const validateEmail = useCallback((value: string): boolean => {
+    if (!value.trim()) {
+      setEmailError('Email is required');
+      return false;
+    }
+    if (!EMAIL_REGEX.test(value.trim())) {
+      setEmailError('Please enter a valid email address');
+      return false;
+    }
+    setEmailError(null);
+    return true;
+  }, []);
+
+  /**
+   * Validate password
+   */
+  const validatePassword = useCallback((value: string): boolean => {
+    if (!value) {
+      setPasswordError('Password is required');
+      return false;
+    }
+    if (value.length < 6) {
+      setPasswordError('Password must be at least 6 characters');
+      return false;
+    }
+    setPasswordError(null);
+    return true;
+  }, []);
+
+  /**
+   * Handle email change
+   */
+  const handleEmailChange = useCallback(
+    (value: string) => {
+      setEmail(value);
+      if (emailError) {
+        setEmailError(null);
+      }
+      if (authError) {
+        clearError();
+      }
+    },
+    [emailError, authError, clearError]
+  );
+
+  /**
+   * Handle password change
+   */
+  const handlePasswordChange = useCallback(
+    (value: string) => {
+      setPassword(value);
+      if (passwordError) {
+        setPasswordError(null);
+      }
+      if (authError) {
+        clearError();
+      }
+    },
+    [passwordError, authError, clearError]
+  );
+
+  /**
+   * Handle login button press
+   */
+  const handleLogin = useCallback(async () => {
+    // Clear previous errors
+    clearError();
+
+    // Validate inputs
+    const isEmailValid = validateEmail(email);
+    const isPasswordValid = validatePassword(password);
+
+    if (!isEmailValid || !isPasswordValid) {
+      return;
+    }
+
+    // Attempt sign in
+    const success = await signIn(email, password);
+
+    if (success) {
+      // Navigate to main app
+      router.replace('/(tabs)');
+    }
+  }, [email, password, signIn, validateEmail, validatePassword, clearError]);
+
+  /**
+   * Handle forgot password link press
+   */
+  const handleForgotPassword = useCallback(() => {
+    Linking.openURL(config.forgotPasswordUrl);
+  }, []);
+
+  /**
+   * Handle email submit (move focus to password)
+   */
+  const handleEmailSubmit = useCallback(() => {
+    passwordInputRef.current?.focus();
+  }, []);
+
+  /**
+   * Get combined error message
+   */
+  const displayError = authError || emailError || passwordError;
+
+  return (
+    <KeyboardAvoidingView
+      style={[styles.container, { backgroundColor: colors.background }]}
+      behavior={Platform.OS === 'ios' ? 'padding' : 'height'}
+    >
+      <ScrollView
+        contentContainerStyle={styles.scrollContent}
+        keyboardShouldPersistTaps="handled"
+        showsVerticalScrollIndicator={false}
+      >
+        <View style={styles.headerContainer}>
+          <Text style={[styles.title, { color: colors.text }]}>Welcome to Makima</Text>
+          <Text style={[styles.subtitle, { color: colors.textSecondary }]}>
+            Sign in to continue
+          </Text>
+        </View>
+
+        <View style={styles.formContainer}>
+          {/* Email Input */}
+          <View style={styles.inputContainer}>
+            <Text style={[styles.label, { color: colors.text }]}>Email</Text>
+            <TextInput
+              style={[
+                styles.input,
+                {
+                  backgroundColor: colors.input,
+                  borderColor: emailError ? colors.error : colors.inputBorder,
+                  color: colors.text,
+                },
+              ]}
+              placeholder="Enter your email"
+              placeholderTextColor={colors.inputPlaceholder}
+              value={email}
+              onChangeText={handleEmailChange}
+              keyboardType="email-address"
+              autoCapitalize="none"
+              autoCorrect={false}
+              autoComplete="email"
+              returnKeyType="next"
+              onSubmitEditing={handleEmailSubmit}
+              editable={!isLoading}
+              testID="email-input"
+            />
+            {emailError && (
+              <Text style={[styles.fieldError, { color: colors.error }]}>{emailError}</Text>
+            )}
+          </View>
+
+          {/* Password Input */}
+          <View style={styles.inputContainer}>
+            <Text style={[styles.label, { color: colors.text }]}>Password</Text>
+            <TextInput
+              ref={passwordInputRef}
+              style={[
+                styles.input,
+                {
+                  backgroundColor: colors.input,
+                  borderColor: passwordError ? colors.error : colors.inputBorder,
+                  color: colors.text,
+                },
+              ]}
+              placeholder="Enter your password"
+              placeholderTextColor={colors.inputPlaceholder}
+              value={password}
+              onChangeText={handlePasswordChange}
+              secureTextEntry
+              autoCapitalize="none"
+              autoCorrect={false}
+              autoComplete="password"
+              returnKeyType="done"
+              onSubmitEditing={handleLogin}
+              editable={!isLoading}
+              testID="password-input"
+            />
+            {passwordError && (
+              <Text style={[styles.fieldError, { color: colors.error }]}>{passwordError}</Text>
+            )}
+          </View>
+
+          {/* Auth Error */}
+          {authError && (
+            <View style={[styles.errorContainer, { backgroundColor: colors.error + '20' }]}>
+              <Text style={[styles.errorText, { color: colors.error }]}>{authError}</Text>
+            </View>
+          )}
+
+          {/* Login Button */}
+          <TouchableOpacity
+            style={[
+              styles.button,
+              {
+                backgroundColor: isLoading ? colors.buttonDisabled : colors.buttonPrimary,
+              },
+            ]}
+            onPress={handleLogin}
+            disabled={isLoading}
+            activeOpacity={0.8}
+            testID="login-button"
+          >
+            {isLoading ? (
+              <ActivityIndicator color={colors.buttonPrimaryText} size="small" />
+            ) : (
+              <Text style={[styles.buttonText, { color: colors.buttonPrimaryText }]}>
+                Sign In
+              </Text>
+            )}
+          </TouchableOpacity>
+
+          {/* Forgot Password Link */}
+          <TouchableOpacity
+            style={styles.forgotPasswordContainer}
+            onPress={handleForgotPassword}
+            disabled={isLoading}
+            testID="forgot-password-link"
+          >
+            <Text style={[styles.forgotPasswordText, { color: colors.link }]}>
+              Forgot Password?
+            </Text>
+          </TouchableOpacity>
+        </View>
+
+        {/* Footer */}
+        <View style={styles.footerContainer}>
+          <Text style={[styles.footerText, { color: colors.textSecondary }]}>
+            By signing in, you agree to our{' '}
+            <Text
+              style={[styles.linkText, { color: colors.link }]}
+              onPress={() => Linking.openURL(config.termsOfServiceUrl)}
+            >
+              Terms of Service
+            </Text>
+            {' and '}
+            <Text
+              style={[styles.linkText, { color: colors.link }]}
+              onPress={() => Linking.openURL(config.privacyPolicyUrl)}
+            >
+              Privacy Policy
+            </Text>
+          </Text>
+        </View>
+      </ScrollView>
+    </KeyboardAvoidingView>
+  );
+}
+
+const styles = StyleSheet.create({
+  container: {
+    flex: 1,
+  },
+  scrollContent: {
+    flexGrow: 1,
+    justifyContent: 'center',
+    paddingHorizontal: 24,
+    paddingVertical: 40,
+  },
+  headerContainer: {
+    alignItems: 'center',
+    marginBottom: 40,
+  },
+  title: {
+    fontSize: 28,
+    fontWeight: 'bold',
+    marginBottom: 8,
+  },
+  subtitle: {
+    fontSize: 16,
+  },
+  formContainer: {
+    width: '100%',
+  },
+  inputContainer: {
+    marginBottom: 20,
+  },
+  label: {
+    fontSize: 14,
+    fontWeight: '600',
+    marginBottom: 8,
+  },
+  input: {
+    height: 50,
+    borderWidth: 1,
+    borderRadius: 12,
+    paddingHorizontal: 16,
+    fontSize: 16,
+  },
+  fieldError: {
+    fontSize: 12,
+    marginTop: 4,
+  },
+  errorContainer: {
+    padding: 12,
+    borderRadius: 8,
+    marginBottom: 20,
+  },
+  errorText: {
+    fontSize: 14,
+    textAlign: 'center',
+  },
+  button: {
+    height: 50,
+    borderRadius: 12,
+    justifyContent: 'center',
+    alignItems: 'center',
+    marginTop: 8,
+  },
+  buttonText: {
+    fontSize: 16,
+    fontWeight: '600',
+  },
+  forgotPasswordContainer: {
+    alignItems: 'center',
+    marginTop: 20,
+  },
+  forgotPasswordText: {
+    fontSize: 14,
+  },
+  footerContainer: {
+    marginTop: 40,
+    alignItems: 'center',
+  },
+  footerText: {
+    fontSize: 12,
+    textAlign: 'center',
+    lineHeight: 18,
+  },
+  linkText: {
+    textDecorationLine: 'underline',
+  },
+});