feat(auth): 手机号验证码登录（会话模型 + 登录页 + 导航接入）

core/data/src/main/kotlin/com/mingyuan/android_client/core/data/di/DataModule.kt

@@ -1,5 +1,10 @@
 package com.mingyuan.android_client.core.data.di
 
+import android.content.Context
+import androidx.datastore.core.DataStore
+import androidx.datastore.preferences.core.PreferenceDataStoreFactory
+import androidx.datastore.preferences.core.Preferences
+import androidx.datastore.preferences.preferencesDataStoreFile
 import com.mingyuan.android_client.core.data.repository.FakeCheckinRepository
 import com.mingyuan.android_client.core.data.repository.FakeHomeRepository
 import com.mingyuan.android_client.core.data.repository.FakePlanRepository
@@ -12,7 +17,9 @@ import com.mingyuan.android_client.core.domain.repository.ProfileRepository
 import com.mingyuan.android_client.core.domain.repository.SessionRepository
 import dagger.Binds
 import dagger.Module
+import dagger.Provides
 import dagger.hilt.InstallIn
+import dagger.hilt.android.qualifiers.ApplicationContext
 import dagger.hilt.components.SingletonComponent
 import javax.inject.Singleton
 
@@ -39,4 +46,11 @@ abstract class DataModule {
     @Binds
     @Singleton
     abstract fun bindSessionRepository(impl: FakeSessionRepository): SessionRepository
+
+    companion object {
+        @Provides
+        @Singleton
+        fun provideSessionDataStore(@ApplicationContext context: Context): DataStore<Preferences> =
+            PreferenceDataStoreFactory.create { context.preferencesDataStoreFile("session") }
+    }
 }

core/data/src/main/kotlin/com/mingyuan/android_client/core/data/repository/FakeSessionRepository.kt

@@ -1,25 +1,71 @@
 package com.mingyuan.android_client.core.data.repository
 
+import androidx.datastore.core.DataStore
+import androidx.datastore.preferences.core.Preferences
+import androidx.datastore.preferences.core.edit
+import androidx.datastore.preferences.core.stringPreferencesKey
+import com.mingyuan.android_client.core.domain.repository.LoginResult
 import com.mingyuan.android_client.core.domain.repository.SessionRepository
+import com.mingyuan.android_client.core.domain.repository.SmsCodeResult
+import com.mingyuan.android_client.core.model.Session
 import kotlinx.coroutines.delay
 import kotlinx.coroutines.flow.Flow
-import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.map
 import javax.inject.Inject
 import javax.inject.Singleton
 
+/**
+ * Local-mock session implementation. It simulates the "phone + SMS code" login flow and persists
+ * the token via DataStore so the login survives process restarts (mirroring the mini-program's
+ * `wx.getStorageSync('token')`). Swap this for a network-backed implementation when the backend
+ * endpoints are ready.
+ *
+ * Mock credentials: phone `13812341234`, code `123456`.
+ */
 @Singleton
-class FakeSessionRepository @Inject constructor() : SessionRepository {
+class FakeSessionRepository @Inject constructor(
+    private val dataStore: DataStore<Preferences>,
+) : SessionRepository {
 
-    private val _isLoggedIn = MutableStateFlow(true)
-    override val isLoggedIn: Flow<Boolean> = _isLoggedIn
+    private companion object {
+        val TOKEN_KEY = stringPreferencesKey("token")
+        const val MOCK_SMS_CODE = "123456"
+        val PHONE_PATTERN = Regex("^1\\d{10}$")
+        // Mirrors the backend's "phone must be pre-provisioned" constraint.
+        val PHONE_WHITELIST = setOf("13812341234")
+    }
 
-    override suspend fun login() {
-        delay(300)
-        _isLoggedIn.value = true
+    private var pendingCode: String? = null
+    private var pendingPhone: String? = null
+
+    override val session: Flow<Session?> = dataStore.data
+        .map { prefs -> prefs[TOKEN_KEY]?.let(::Session) }
+
+    override suspend fun requestSmsCode(phone: String): SmsCodeResult {
+        if (!PHONE_PATTERN.matches(phone)) {
+            return SmsCodeResult.Failure("请输入正确的手机号")
+        }
+        delay(500)
+        pendingPhone = phone
+        pendingCode = MOCK_SMS_CODE
+        return SmsCodeResult.Success
+    }
+
+    override suspend fun login(phone: String, code: String): LoginResult {
+        if (phone != pendingPhone || code != pendingCode) {
+            return LoginResult.Failure("验证码错误")
+        }
+        if (phone !in PHONE_WHITELIST) {
+            return LoginResult.Failure("手机号未匹配，无法登录")
+        }
+        delay(500)
+        dataStore.edit { it[TOKEN_KEY] = "mock-token-$phone" }
+        pendingPhone = null
+        pendingCode = null
+        return LoginResult.Success
     }
 
     override suspend fun logout() {
-        delay(300)
-        _isLoggedIn.value = false
+        dataStore.edit { it.remove(TOKEN_KEY) }
     }
 }