diff --git a/app/src/main/kotlin/top/yeij/cyrene/app/AppContainer.kt b/app/src/main/kotlin/top/yeij/cyrene/app/AppContainer.kt
index 003c3a5..43aba42 100644
--- a/app/src/main/kotlin/top/yeij/cyrene/app/AppContainer.kt
+++ b/app/src/main/kotlin/top/yeij/cyrene/app/AppContainer.kt
@@ -3,9 +3,45 @@ package top.yeij.cyrene.app
 import android.content.Context
 import top.yeij.cyrene.core.auth.AuthManager
 import top.yeij.cyrene.core.auth.SessionStore
+import top.yeij.cyrene.data.api.ApiClientFactory
+import top.yeij.cyrene.data.api.SessionsApi
+import top.yeij.cyrene.data.repository.MessageRepository
+import top.yeij.cyrene.data.repository.SessionRepository
+import top.yeij.cyrene.data.ws.ChatSocket
 
 /** 手写 DI 容器（D：不引 Hilt）。 */
 class AppContainer(context: Context) {
+
     val sessionStore: SessionStore = SessionStore(context.applicationContext)
     val authManager: AuthManager = AuthManager(sessionStore)
+
+    private var cachedBaseUrl: String? = null
+    private var cachedSessionsApi: SessionsApi? = null
+
+    /** 会话/消息 REST 客户端；baseUrl 变化时自动重建。 */
+    val sessionsApi: SessionsApi
+        get() {
+            val baseUrl = authManager.currentBaseUrl
+            val cached = cachedSessionsApi
+            if (cached != null && cachedBaseUrl == baseUrl) return cached
+            val created = ApiClientFactory.create(
+                baseUrl = baseUrl,
+                service = SessionsApi::class.java,
+                tokenProvider = { sessionStore.load().token },
+                onUnauthorized = { authManager.onSessionExpired() },
+            )
+            cachedBaseUrl = baseUrl
+            cachedSessionsApi = created
+            return created
+        }
+
+    val sessionRepository: SessionRepository get() = SessionRepository(sessionsApi)
+
+    val messageRepository: MessageRepository get() = MessageRepository(sessionsApi)
+
+    fun createChatSocket(): ChatSocket = ChatSocket(
+        baseUrlProvider = { authManager.currentBaseUrl },
+        tokenProvider = { sessionStore.load().token },
+        onAuthFailed = { authManager.onSessionExpired() },
+    )
 }
diff --git a/app/src/main/kotlin/top/yeij/cyrene/app/CyreneApp.kt b/app/src/main/kotlin/top/yeij/cyrene/app/CyreneApp.kt
index c8cd05c..4926996 100644
--- a/app/src/main/kotlin/top/yeij/cyrene/app/CyreneApp.kt
+++ b/app/src/main/kotlin/top/yeij/cyrene/app/CyreneApp.kt
@@ -5,8 +5,8 @@ import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.collectAsState
 import androidx.compose.runtime.getValue
 import top.yeij.cyrene.core.auth.SessionState
+import top.yeij.cyrene.ui.chat.ChatScreen
 import top.yeij.cyrene.ui.common.LoadingScreen
-import top.yeij.cyrene.ui.home.HomeScreen
 import top.yeij.cyrene.ui.login.LoginScreen
 
 @Composable
@@ -20,7 +20,8 @@ fun CyreneApp(container: AppContainer) {
     when (state) {
         SessionState.Unknown -> LoadingScreen()
         SessionState.LoggedOut -> LoginScreen(container)
-        is SessionState.LoggedIn -> HomeScreen(
+        is SessionState.LoggedIn -> ChatScreen(
+            container = container,
             onLogout = { container.authManager.logout() },
         )
     }
diff --git a/app/src/main/kotlin/top/yeij/cyrene/data/api/ApiClientFactory.kt b/app/src/main/kotlin/top/yeij/cyrene/data/api/ApiClientFactory.kt
index a43da49..3ade1d8 100644
--- a/app/src/main/kotlin/top/yeij/cyrene/data/api/ApiClientFactory.kt
+++ b/app/src/main/kotlin/top/yeij/cyrene/data/api/ApiClientFactory.kt
@@ -19,11 +19,20 @@ object ApiClientFactory {
         coerceInputValues = true
     }
 
+    /** 登录接口（不注入 token）。 */
     fun create(
         baseUrl: String,
         tokenProvider: () -> String? = { null },
         onUnauthorized: () -> Unit = {},
-    ): CyreneApi {
+    ): CyreneApi = create(baseUrl, CyreneApi::class.java, tokenProvider, onUnauthorized)
+
+    /** 通用入口：按需构建任意 Retrofit service。 */
+    fun <T : Any> create(
+        baseUrl: String,
+        service: Class<T>,
+        tokenProvider: () -> String? = { null },
+        onUnauthorized: () -> Unit = {},
+    ): T {
         val client = OkHttpClient.Builder()
             .connectTimeout(10, TimeUnit.SECONDS)
             .readTimeout(60, TimeUnit.SECONDS)
@@ -46,7 +55,7 @@ object ApiClientFactory {
             .client(client)
             .addConverterFactory(json.asConverterFactory("application/json".toMediaType()))
             .build()
-            .create(CyreneApi::class.java)
+            .create(service)
     }
 
     /** Retrofit 要求 baseUrl 以 `/` 结尾；用户没写 scheme 时补 `http://`。 */
diff --git a/app/src/main/kotlin/top/yeij/cyrene/ui/chat/ChatScreen.kt b/app/src/main/kotlin/top/yeij/cyrene/ui/chat/ChatScreen.kt
new file mode 100644
index 0000000..abb0dc8
--- /dev/null
+++ b/app/src/main/kotlin/top/yeij/cyrene/ui/chat/ChatScreen.kt
@@ -0,0 +1,189 @@
+package top.yeij.cyrene.ui.chat
+
+import androidx.compose.foundation.background
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.PaddingValues
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.widthIn
+import androidx.compose.foundation.lazy.LazyColumn
+import androidx.compose.foundation.lazy.items
+import androidx.compose.foundation.lazy.rememberLazyListState
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.snapshotFlow
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.unit.dp
+import androidx.lifecycle.viewmodel.compose.viewModel
+import androidx.lifecycle.viewmodel.initializer
+import androidx.lifecycle.viewmodel.viewModelFactory
+import kotlinx.coroutines.flow.distinctUntilChanged
+import top.yeij.cyrene.app.AppContainer
+import top.yeij.cyrene.data.api.dto.HistoryMessageDto
+import top.yeij.cyrene.data.ws.WsState
+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 ChatScreen(
+    container: AppContainer,
+    onOpenDrawer: () -> Unit = {},
+    onLogout: () -> Unit = {},
+) {
+    val viewModel: ChatViewModel = viewModel(
+        factory = viewModelFactory { initializer { ChatViewModel(container) } },
+    )
+    val state by viewModel.state.collectAsState()
+    val listState = rememberLazyListState()
+
+    // reverseLayout 下「列表末尾」就是屏幕顶部；接近末尾时加载更早的一页。
+    LaunchedEffect(listState) {
+        snapshotFlow {
+            val info = listState.layoutInfo
+            val lastVisible = info.visibleItemsInfo.lastOrNull()?.index ?: -1
+            info.totalItemsCount > 0 && lastVisible >= info.totalItemsCount - 2
+        }
+            .distinctUntilChanged()
+            .collect { nearTop -> if (nearTop) viewModel.loadOlder() }
+    }
+
+    Scaffold(
+        topBar = {
+            SmallTopAppBar(
+                title = "与昔涟",
+                subtitle = statusLabel(state),
+                navigationIcon = {
+                    IconButton(onClick = onOpenDrawer) {
+                        Icon(imageVector = MiuixIcons.Basic.Sidebar, contentDescription = "菜单")
+                    }
+                },
+                actions = {
+                    TextButton("登出", onClick = onLogout)
+                },
+            )
+        },
+    ) { padding ->
+        Box(
+            modifier = Modifier
+                .fillMaxSize()
+                .padding(padding),
+        ) {
+            when {
+                state.loading && state.messages.isEmpty() -> CenterHint("加载中…")
+                state.messages.isEmpty() -> CenterHint("还没有消息")
+                else -> LazyColumn(
+                    state = listState,
+                    reverseLayout = true,
+                    modifier = Modifier.fillMaxSize(),
+                    contentPadding = PaddingValues(vertical = 12.dp),
+                    verticalArrangement = Arrangement.spacedBy(10.dp),
+                ) {
+                    items(items = state.messages.asReversed(), key = { it.id }) { message ->
+                        MessageBubble(message)
+                    }
+                    if (state.hasMore) {
+                        item(key = "__load_older__") {
+                            Box(
+                                modifier = Modifier
+                                    .fillMaxWidth()
+                                    .padding(vertical = 16.dp),
+                                contentAlignment = Alignment.Center,
+                            ) {
+                                Text(
+                                    text = if (state.loadingOlder) "加载更早的消息…" else "上滑加载更早的消息",
+                                    style = MiuixTheme.textStyles.footnote2,
+                                    color = MiuixTheme.colorScheme.onSurfaceVariantSummary,
+                                )
+                            }
+                        }
+                    }
+                }
+            }
+
+            state.error?.let { message ->
+                Text(
+                    text = message,
+                    style = MiuixTheme.textStyles.footnote1,
+                    color = MiuixTheme.colorScheme.error,
+                    modifier = Modifier
+                        .align(Alignment.TopCenter)
+                        .fillMaxWidth()
+                        .background(MiuixTheme.colorScheme.surfaceContainer)
+                        .padding(12.dp),
+                )
+            }
+        }
+    }
+}
+
+@Composable
+private fun MessageBubble(message: HistoryMessageDto) {
+    val isUser = message.role == "user"
+    val bubbleColor = if (isUser) MiuixTheme.colorScheme.primary else MiuixTheme.colorScheme.surfaceContainer
+    val textColor = if (isUser) MiuixTheme.colorScheme.onPrimary else MiuixTheme.colorScheme.onSurfaceContainer
+
+    Column(
+        modifier = Modifier
+            .fillMaxWidth()
+            .padding(horizontal = 14.dp),
+        horizontalAlignment = if (isUser) Alignment.End else Alignment.Start,
+    ) {
+        Box(
+            modifier = Modifier
+                .widthIn(max = 300.dp)
+                .background(color = bubbleColor, shape = RoundedCornerShape(18.dp))
+                .padding(horizontal = 14.dp, vertical = 10.dp),
+        ) {
+            Text(
+                text = message.content,
+                style = MiuixTheme.textStyles.main,
+                color = textColor,
+            )
+        }
+        messageSourceLabel(message)?.let { source ->
+            Text(
+                text = source,
+                style = MiuixTheme.textStyles.footnote2,
+                color = MiuixTheme.colorScheme.onSurfaceVariantSummary,
+                modifier = Modifier.padding(top = 3.dp, start = 6.dp, end = 6.dp),
+            )
+        }
+    }
+}
+
+@Composable
+private fun CenterHint(text: String) {
+    Box(modifier = Modifier.fillMaxSize(), contentAlignment = Alignment.Center) {
+        Text(
+            text = text,
+            style = MiuixTheme.textStyles.main,
+            color = MiuixTheme.colorScheme.onSurfaceVariantSummary,
+        )
+    }
+}
+
+private fun statusLabel(state: ChatUiState): String = when {
+    state.busyMode != null && state.queueDepth > 0 -> "正在思考… 已排队 ${state.queueDepth} 条"
+    state.busyMode != null -> "正在思考…"
+    else -> when (state.connection) {
+        WsState.Connected -> "已连接"
+        WsState.Connecting -> "连接中…"
+        WsState.Reconnecting -> "重连中…"
+        WsState.Offline -> "离线"
+        WsState.Idle -> ""
+    }
+}
diff --git a/app/src/main/kotlin/top/yeij/cyrene/ui/chat/ChatViewModel.kt b/app/src/main/kotlin/top/yeij/cyrene/ui/chat/ChatViewModel.kt
new file mode 100644
index 0000000..2ae4ccb
--- /dev/null
+++ b/app/src/main/kotlin/top/yeij/cyrene/ui/chat/ChatViewModel.kt
@@ -0,0 +1,177 @@
+package top.yeij.cyrene.ui.chat
+
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.viewModelScope
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
+import kotlinx.coroutines.flow.update
+import kotlinx.coroutines.launch
+import top.yeij.cyrene.app.AppContainer
+import top.yeij.cyrene.data.api.CyreneException
+import top.yeij.cyrene.data.api.dto.HistoryMessageDto
+import top.yeij.cyrene.data.repository.MessageRepository
+import top.yeij.cyrene.data.repository.mergeMessages
+import top.yeij.cyrene.data.ws.ChatSocket
+import top.yeij.cyrene.data.ws.WsEvent
+import top.yeij.cyrene.data.ws.WsState
+
+const val MAIN_SESSION_ID = "web"
+
+data class ChatUiState(
+    /** 升序（旧 → 新）；渲染时反向喂给 reverseLayout 的列表。 */
+    val messages: List<HistoryMessageDto> = emptyList(),
+    val loading: Boolean = true,
+    val loadingOlder: Boolean = false,
+    val hasMore: Boolean = true,
+    val error: String? = null,
+    val connection: WsState = WsState.Idle,
+    /** 编排忙碌态（`idle`/`thinking`/`executing`/`subagent`），null = 空闲。 */
+    val busyMode: String? = null,
+    val queueDepth: Int = 0,
+)
+
+/**
+ * M2：只读主会话。
+ *
+ * 数据来源三路合并（都走 `mergeMessages` 按 `id` 去重）：
+ * 1. REST 首屏 `loadLatest`（权威、带分页游标）
+ * 2. WS 首帧 `history`（与 REST 重叠，靠 id 去重收敛）
+ * 3. WS 增量 `message_persisted`（其它端/本端落库后的消息）
+ *
+ * 注意（D14）：结构化流帧不带 `sessionId`，同一时刻只允许一个会话在流式；
+ * 当前只有主会话，暂不涉及归属问题。
+ */
+class ChatViewModel(
+    private val container: AppContainer,
+    private val sessionId: String = MAIN_SESSION_ID,
+) : ViewModel() {
+
+    private val _state = MutableStateFlow(ChatUiState())
+    val state: StateFlow<ChatUiState> = _state.asStateFlow()
+
+    private var socket: ChatSocket? = null
+    private var repository: MessageRepository? = null
+    private var oldestLoadedAt: Long? = null
+
+    init {
+        start()
+    }
+
+    private fun start() {
+        val repo = container.messageRepository
+        repository = repo
+
+        viewModelScope.launch {
+            repo.loadLatest(sessionId)
+                .onSuccess { page ->
+                    oldestLoadedAt = page.oldestCreatedAt
+                    _state.update {
+                        it.copy(
+                            messages = mergeMessages(it.messages, page.messages),
+                            loading = false,
+                            hasMore = page.hasMore,
+                            error = null,
+                        )
+                    }
+                }
+                .onFailure { e ->
+                    _state.update { it.copy(loading = false, error = e.userMessage()) }
+                }
+        }
+
+        val ws = container.createChatSocket()
+        socket = ws
+        viewModelScope.launch {
+            ws.state.collect { connection -> _state.update { it.copy(connection = connection) } }
+        }
+        viewModelScope.launch {
+            ws.events.collect(::onEvent)
+        }
+        ws.connect()
+    }
+
+    private fun onEvent(event: WsEvent) {
+        when (event) {
+            is WsEvent.History -> {
+                val incoming = event.messages
+                if (incoming.isEmpty()) {
+                    _state.update { it.copy(loading = false) }
+                } else {
+                    val oldest = incoming.minOf { it.createdAt }
+                    oldestLoadedAt = oldestLoadedAt?.let { minOf(it, oldest) } ?: oldest
+                    _state.update {
+                        it.copy(messages = mergeMessages(it.messages, incoming), loading = false)
+                    }
+                }
+            }
+
+            is WsEvent.MessagePersisted -> {
+                val message = event.message ?: return
+                if (message.sessionId != sessionId) return
+                _state.update { it.copy(messages = mergeMessages(it.messages, listOf(message))) }
+            }
+
+            is WsEvent.SessionBusy -> if (event.sessionId == sessionId) {
+                _state.update { it.copy(busyMode = event.mode) }
+            }
+
+            is WsEvent.PendingAck -> if (event.sessionId == sessionId) {
+                _state.update { it.copy(busyMode = event.mode, queueDepth = event.queueDepth) }
+            }
+
+            is WsEvent.PendingDrain -> if (event.sessionId == sessionId) {
+                _state.update { it.copy(queueDepth = event.queueDepth) }
+            }
+
+            is WsEvent.SessionIdle -> if (event.sessionId == sessionId) {
+                _state.update { it.copy(busyMode = null, queueDepth = 0) }
+            }
+
+            is WsEvent.SessionInterrupted -> if (event.sessionId == sessionId) {
+                _state.update { it.copy(busyMode = null, queueDepth = 0) }
+            }
+
+            is WsEvent.Error -> _state.update { it.copy(error = event.message) }
+
+            else -> Unit // 流式/思维链/工具卡等留到 M3、M4
+        }
+    }
+
+    /** 上拉加载更早的一页（`before` 游标 = 当前已加载最旧一条的 createdAt）。 */
+    fun loadOlder() {
+        val repo = repository ?: return
+        val before = oldestLoadedAt ?: return
+        val snapshot = _state.value
+        if (snapshot.loadingOlder || !snapshot.hasMore) return
+
+        _state.update { it.copy(loadingOlder = true) }
+        viewModelScope.launch {
+            repo.loadPage(sessionId, before = before)
+                .onSuccess { page ->
+                    if (page.oldestCreatedAt != null) oldestLoadedAt = page.oldestCreatedAt
+                    _state.update {
+                        it.copy(
+                            messages = mergeMessages(it.messages, page.messages),
+                            loadingOlder = false,
+                            hasMore = page.hasMore && page.messages.isNotEmpty(),
+                        )
+                    }
+                }
+                .onFailure { e ->
+                    _state.update { it.copy(loadingOlder = false, error = e.userMessage()) }
+                }
+        }
+    }
+
+    fun dismissError() = _state.update { it.copy(error = null) }
+
+    override fun onCleared() {
+        socket?.close()
+        socket = null
+        super.onCleared()
+    }
+}
+
+private fun Throwable.userMessage(): String =
+    (this as? CyreneException)?.error?.userMessage ?: "加载失败，请稍后重试"
diff --git a/app/src/main/kotlin/top/yeij/cyrene/ui/chat/MessageSource.kt b/app/src/main/kotlin/top/yeij/cyrene/ui/chat/MessageSource.kt
new file mode 100644
index 0000000..6a1c6fd
--- /dev/null
+++ b/app/src/main/kotlin/top/yeij/cyrene/ui/chat/MessageSource.kt
@@ -0,0 +1,34 @@
+package top.yeij.cyrene.ui.chat
+
+import top.yeij.cyrene.data.api.dto.HistoryMessageDto
+
+private val platformLabels = mapOf(
+    "web" to "Web",
+    "kook" to "KOOK",
+    "weixin-ilink" to "微信",
+    "qq-obv11" to "QQ",
+    "telegram" to "Telegram",
+    "webhook" to "Webhook",
+)
+
+/**
+ * 来源角标（S1.3）：每条消息默认显示来源。
+ * 优先用 `deviceId` 区分具体端，再回落到 `platform`；两者都没有则返回 null（不显示）。
+ */
+fun messageSourceLabel(message: HistoryMessageDto): String? {
+    val deviceId = message.deviceId
+    if (!deviceId.isNullOrBlank()) {
+        if (deviceId.startsWith("voiceassist")) return "来自安卓"
+        if (deviceId.startsWith("web:")) {
+            val browser = deviceId.removePrefix("web:").substringBefore(':')
+            return "来自 Web($browser)"
+        }
+        return "来自 $deviceId"
+    }
+
+    val platform = message.platform
+    if (!platform.isNullOrBlank()) {
+        return "来自 ${platformLabels[platform] ?: platform}"
+    }
+    return null
+}
diff --git a/app/src/main/kotlin/top/yeij/cyrene/ui/home/HomeScreen.kt b/app/src/main/kotlin/top/yeij/cyrene/ui/home/HomeScreen.kt
deleted file mode 100644
index ccacd33..0000000
--- a/app/src/main/kotlin/top/yeij/cyrene/ui/home/HomeScreen.kt
+++ /dev/null
@@ -1,52 +0,0 @@
-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,
-            )
-        }
-    }
-}
diff --git a/gradle.properties b/gradle.properties
index f459e5b..5b8a2cb 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -6,10 +6,4 @@ org.gradle.configuration-cache=false
 android.useAndroidX=true
 android.nonTransitiveRClass=true
 
-# 本机无法访问 dl.google.com，禁止 AGP 尝试联网下载 SDK 组件（否则会卡住）
-android.builder.sdkDownload=false
-
 kotlin.code.style=official
-
-# ARM64 机器：Google Maven 只提供 x86_64 的 aapt2，改用本机 ARM64 版本
-android.aapt2FromMavenOverride=/home/Aska/Android/Sdk/build-tools/37.0.0/aapt2