feat: 初始化 Android 客户端（M0 骨架 + M1 登录 + M2 基础模块）

M0：Gradle 9.7.1 / AGP 9.2.1 / Kotlin 2.4 / Miuix 0.9.3，minSdk 33，compileSdk 37。
M1：登录页（服务器地址可配、服务端/本地错误分流、EncryptedSharedPreferences、自动登录与静默重登、401 登出）。
M2 基础模块：消息内容解析器（<p>/<action>/<narration> + 流式增量）、WebSocket 客户端、REST 数据层与分页去重。
45 个单元测试全绿，真机验证通过（登录页 + 启动图标）。
devdocs/ 收录设计文档、前后端协同事项与细化方案。

app/src/main/kotlin/top/yeij/cyrene/ui/common/LoadingScreen.kt

@@ -0,0 +1,25 @@
+package top.yeij.cyrene.ui.common
+
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.padding
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import top.yukonga.miuix.kmp.basic.Scaffold
+import top.yukonga.miuix.kmp.basic.Text
+import top.yukonga.miuix.kmp.theme.MiuixTheme
+
+@Composable
+fun LoadingScreen() {
+    Scaffold { padding ->
+        Box(
+            modifier = Modifier
+                .fillMaxSize()
+                .padding(padding),
+            contentAlignment = Alignment.Center,
+        ) {
+            Text("加载中…", style = MiuixTheme.textStyles.main)
+        }
+    }
+}

app/src/main/kotlin/top/yeij/cyrene/ui/home/HomeScreen.kt

@@ -0,0 +1,52 @@
+package top.yeij.cyrene.ui.home
+
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.padding
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import top.yukonga.miuix.kmp.basic.Icon
+import top.yukonga.miuix.kmp.basic.IconButton
+import top.yukonga.miuix.kmp.basic.Scaffold
+import top.yukonga.miuix.kmp.basic.SmallTopAppBar
+import top.yukonga.miuix.kmp.basic.Text
+import top.yukonga.miuix.kmp.basic.TextButton
+import top.yukonga.miuix.kmp.icon.MiuixIcons
+import top.yukonga.miuix.kmp.icon.basic.Sidebar
+import top.yukonga.miuix.kmp.theme.MiuixTheme
+
+@Composable
+fun HomeScreen(onLogout: () -> Unit = {}) {
+    Scaffold(
+        topBar = {
+            SmallTopAppBar(
+                title = "Cyrene",
+                navigationIcon = {
+                    IconButton(onClick = { /* M5：打开侧边栏 */ }) {
+                        Icon(imageVector = MiuixIcons.Basic.Sidebar, contentDescription = "菜单")
+                    }
+                },
+                actions = {
+                    TextButton("登出", onClick = onLogout)
+                },
+            )
+        },
+    ) { padding ->
+        Column(
+            modifier = Modifier
+                .fillMaxSize()
+                .padding(padding),
+            verticalArrangement = Arrangement.Center,
+            horizontalAlignment = Alignment.CenterHorizontally,
+        ) {
+            Text(text = "与昔涟", style = MiuixTheme.textStyles.title2)
+            Text(
+                text = "会话列表 · 规划中",
+                style = MiuixTheme.textStyles.footnote1,
+                color = MiuixTheme.colorScheme.onSurfaceContainerVariant,
+            )
+        }
+    }
+}

app/src/main/kotlin/top/yeij/cyrene/ui/login/LoginScreen.kt

@@ -0,0 +1,143 @@
+package top.yeij.cyrene.ui.login
+
+import androidx.compose.foundation.clickable
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.rememberScrollState
+import androidx.compose.foundation.text.KeyboardActions
+import androidx.compose.foundation.text.KeyboardOptions
+import androidx.compose.foundation.verticalScroll
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.getValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.text.input.ImeAction
+import androidx.compose.ui.text.input.KeyboardType
+import androidx.compose.ui.text.input.PasswordVisualTransformation
+import androidx.compose.ui.text.input.VisualTransformation
+import androidx.compose.ui.unit.dp
+import androidx.lifecycle.viewmodel.compose.viewModel
+import androidx.lifecycle.viewmodel.initializer
+import androidx.lifecycle.viewmodel.viewModelFactory
+import top.yeij.cyrene.app.AppContainer
+import top.yukonga.miuix.kmp.basic.Button
+import top.yukonga.miuix.kmp.basic.IconButton
+import top.yukonga.miuix.kmp.basic.Scaffold
+import top.yukonga.miuix.kmp.basic.Text
+import top.yukonga.miuix.kmp.basic.TextField
+import top.yukonga.miuix.kmp.theme.MiuixTheme
+
+@Composable
+fun LoginScreen(container: AppContainer) {
+    val viewModel: LoginViewModel = viewModel(
+        factory = viewModelFactory {
+            initializer { LoginViewModel(container.authManager, container.sessionStore) }
+        },
+    )
+    val state by viewModel.state.collectAsState()
+
+    Scaffold { padding ->
+        Column(
+            modifier = Modifier
+                .fillMaxSize()
+                .padding(padding)
+                .verticalScroll(rememberScrollState())
+                .padding(horizontal = 24.dp),
+            horizontalAlignment = Alignment.CenterHorizontally,
+        ) {
+            Spacer(Modifier.height(72.dp))
+            Text("Cyrene", style = MiuixTheme.textStyles.title1)
+            Spacer(Modifier.height(4.dp))
+            Text(
+                text = "登录后与昔涟聊天",
+                style = MiuixTheme.textStyles.footnote1,
+                color = MiuixTheme.colorScheme.onSurfaceVariantSummary,
+            )
+            Spacer(Modifier.height(32.dp))
+
+            Text(
+                text = if (state.serverExpanded) "服务器地址（点击收起）" else "服务器地址（点击展开）",
+                style = MiuixTheme.textStyles.subtitle,
+                modifier = Modifier
+                    .fillMaxWidth()
+                    .clickable { viewModel.toggleServerExpanded() }
+                    .padding(vertical = 8.dp),
+            )
+            if (state.serverExpanded) {
+                TextField(
+                    value = state.baseUrl,
+                    onValueChange = viewModel::onBaseUrlChange,
+                    label = "http://192.168.1.10:8080",
+                    singleLine = true,
+                    keyboardOptions = KeyboardOptions(
+                        keyboardType = KeyboardType.Uri,
+                        imeAction = ImeAction.Next,
+                    ),
+                    modifier = Modifier.fillMaxWidth(),
+                )
+                Spacer(Modifier.height(12.dp))
+            }
+
+            TextField(
+                value = state.username,
+                onValueChange = viewModel::onUsernameChange,
+                label = "用户名",
+                singleLine = true,
+                keyboardOptions = KeyboardOptions(imeAction = ImeAction.Next),
+                modifier = Modifier.fillMaxWidth(),
+            )
+            Spacer(Modifier.height(12.dp))
+
+            TextField(
+                value = state.password,
+                onValueChange = viewModel::onPasswordChange,
+                label = "密码",
+                singleLine = true,
+                visualTransformation = if (state.passwordVisible) {
+                    VisualTransformation.None
+                } else {
+                    PasswordVisualTransformation()
+                },
+                keyboardOptions = KeyboardOptions(
+                    keyboardType = KeyboardType.Password,
+                    imeAction = ImeAction.Done,
+                ),
+                keyboardActions = KeyboardActions(onDone = { viewModel.submit() }),
+                trailingIcon = {
+                    IconButton(onClick = viewModel::togglePasswordVisible) {
+                        Text(
+                            text = if (state.passwordVisible) "隐藏" else "显示",
+                            style = MiuixTheme.textStyles.footnote1,
+                        )
+                    }
+                },
+                modifier = Modifier.fillMaxWidth(),
+            )
+
+            if (state.error != null) {
+                Spacer(Modifier.height(12.dp))
+                Text(
+                    text = state.error.orEmpty(),
+                    style = MiuixTheme.textStyles.footnote1,
+                    color = MiuixTheme.colorScheme.error,
+                    modifier = Modifier.fillMaxWidth(),
+                )
+            }
+
+            Spacer(Modifier.height(28.dp))
+            Button(
+                onClick = viewModel::submit,
+                enabled = !state.loading,
+                modifier = Modifier.fillMaxWidth(),
+            ) {
+                Text(if (state.loading) "登录中…" else "登录")
+            }
+            Spacer(Modifier.height(32.dp))
+        }
+    }
+}

app/src/main/kotlin/top/yeij/cyrene/ui/login/LoginViewModel.kt

@@ -0,0 +1,73 @@
+package top.yeij.cyrene.ui.login
+
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.viewModelScope
+import top.yeij.cyrene.core.auth.AuthManager
+import top.yeij.cyrene.core.auth.SessionStore
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
+import kotlinx.coroutines.flow.update
+import kotlinx.coroutines.launch
+
+data class LoginUiState(
+    val baseUrl: String = "",
+    val username: String = "",
+    val password: String = "",
+    val passwordVisible: Boolean = false,
+    val serverExpanded: Boolean = false,
+    val loading: Boolean = false,
+    val error: String? = null,
+)
+
+class LoginViewModel(
+    private val authManager: AuthManager,
+    sessionStore: SessionStore,
+) : ViewModel() {
+
+    private val _state = MutableStateFlow(LoginUiState())
+    val state: StateFlow<LoginUiState> = _state.asStateFlow()
+
+    init {
+        val stored = sessionStore.load()
+        _state.update {
+            it.copy(
+                baseUrl = stored.baseUrl,
+                username = stored.username.orEmpty(),
+                serverExpanded = stored.baseUrl.isBlank(),
+            )
+        }
+    }
+
+    fun onBaseUrlChange(value: String) = _state.update { it.copy(baseUrl = value, error = null) }
+
+    fun onUsernameChange(value: String) = _state.update { it.copy(username = value, error = null) }
+
+    fun onPasswordChange(value: String) = _state.update { it.copy(password = value, error = null) }
+
+    fun togglePasswordVisible() = _state.update { it.copy(passwordVisible = !it.passwordVisible) }
+
+    fun toggleServerExpanded() = _state.update { it.copy(serverExpanded = !it.serverExpanded) }
+
+    fun submit() {
+        val snapshot = _state.value
+        if (snapshot.loading) return
+
+        val validationError = when {
+            snapshot.baseUrl.isBlank() -> "请填写服务器地址"
+            snapshot.username.isBlank() -> "请填写用户名"
+            snapshot.password.isBlank() -> "请填写密码"
+            else -> null
+        }
+        if (validationError != null) {
+            _state.update { it.copy(error = validationError, serverExpanded = true) }
+            return
+        }
+
+        _state.update { it.copy(loading = true, error = null) }
+        viewModelScope.launch {
+            val error = authManager.login(snapshot.baseUrl, snapshot.username.trim(), snapshot.password)
+            _state.update { it.copy(loading = false, error = error?.userMessage) }
+        }
+    }
+}