feat(app): add authenticated app shell with top bar and bottom navigation (#6)

### 概述 / Summary
实现认证后的主应用壳层（`MainAppShell`），包含胶囊顶栏（`ABoxTopPillBar`）与 Material 3 底部导航栏（`ABoxNavigationBar`），并为团队其他成员预留标准 Composable 插槽。

### 核心变更 / Changes
1. **设计系统 (`:android:core:designsystem`)**：
   - 新增 `ABoxTopPillBar`：展示提供方/空间信息、快捷 `+` 操作与用户头像徽标。
   - 新增 `ABoxUserAvatar`：支持用户名首字符与主题强调轮廓。
   - 新增 `ABoxNavigationBar` & `ABoxNavigationBarItem`：M3 胶囊指示器底部导航栏封装。
2. **应用壳层 (`:android:app`)**：
   - 新增 `MainTab`（`DEVICES`, `SCENES`, `ACTIVITY`），严格对齐需求与分工术语。
   - 新增 `MainAppShell`：承载顶栏、底栏、Tab 平滑切换，并开放 `devicesSlot`、`scenesSlot`、`activitySlot`。
   - 新增 `AccountProviderBottomSheet`：点击头像展示当前会话/提供方信息、支持切换提供方与退出登录。
3. **多语言与测试**：
   - 补充 `values` 与 `values-zh-rCN` 双语资源。
   - 新增 `MainTabTest` 单元测试并通过全量 `check` 与 `test`。

### 分工保护 / Boundaries
- 仅提供顶栏、底栏与主页面容器骨架；
- 设备列表、情景编排与设备控制详情的具体 UI 保持为插槽，供 alZerNest、tzh 和 Aurum 后续无缝填充。

Reviewed-on: #6
Co-authored-by: KremeCN <3265494849@qq.com>

android/core/designsystem/build.gradle.kts

@@ -34,5 +34,6 @@ dependencies {
     implementation(libs.compose.ui)
     implementation(libs.compose.ui.tooling.preview)
     implementation(libs.compose.material3)
+    implementation(libs.compose.material.icons.extended)
     debugImplementation(libs.compose.ui.tooling)
 }

android/core/designsystem/src/main/kotlin/com/flagship/abox/manager/designsystem/Components.kt

@@ -1,12 +1,43 @@
 package com.flagship.abox.manager.designsystem
 
+import androidx.compose.foundation.background
+import androidx.compose.foundation.border
+import androidx.compose.foundation.clickable
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Row
 import androidx.compose.foundation.layout.RowScope
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.shape.CircleShape
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.Add
+import androidx.compose.material.icons.filled.LocationOn
+import androidx.compose.material.icons.filled.Person
 import androidx.compose.material3.Button
 import androidx.compose.material3.ButtonDefaults
 import androidx.compose.material3.CircularProgressIndicator
+import androidx.compose.material3.Icon
+import androidx.compose.material3.IconButton
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.NavigationBar
+import androidx.compose.material3.NavigationBarItem
+import androidx.compose.material3.NavigationBarItemDefaults
 import androidx.compose.material3.Surface
+import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
+import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.clip
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.graphics.vector.ImageVector
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.text.style.TextOverflow
+import androidx.compose.ui.unit.Dp
+import androidx.compose.ui.unit.dp
 
 @Composable
 fun ABoxSurface(
@@ -36,3 +67,162 @@ fun ABoxButton(
 fun ABoxLoadingIndicator(modifier: Modifier = Modifier) {
     CircularProgressIndicator(modifier = modifier)
 }
+
+/**
+ * Circular user avatar displaying the initial character of username or a default person icon.
+ * Styled with an accented profile ring.
+ */
+@Composable
+fun ABoxUserAvatar(
+    name: String?,
+    onClick: () -> Unit,
+    modifier: Modifier = Modifier,
+    size: Dp = 36.dp,
+    contentDescription: String? = null,
+) {
+    val initial = name?.trim()?.takeIf { it.isNotEmpty() }?.take(1)?.uppercase()
+    Box(
+        modifier = modifier
+            .size(size)
+            .clip(CircleShape)
+            .background(MaterialTheme.colorScheme.primaryContainer)
+            .border(
+                width = 2.dp,
+                color = MaterialTheme.colorScheme.primary.copy(alpha = 0.8f),
+                shape = CircleShape,
+            )
+            .clickable(onClickLabel = contentDescription, onClick = onClick),
+        contentAlignment = Alignment.Center,
+    ) {
+        if (initial != null) {
+            Text(
+                text = initial,
+                style = MaterialTheme.typography.titleMedium.copy(
+                    fontWeight = FontWeight.Bold,
+                    color = MaterialTheme.colorScheme.onPrimaryContainer,
+                ),
+            )
+        } else {
+            Icon(
+                imageVector = Icons.Default.Person,
+                contentDescription = contentDescription,
+                tint = MaterialTheme.colorScheme.onPrimaryContainer,
+                modifier = Modifier.size(size * 0.6f),
+            )
+        }
+    }
+}
+
+/**
+ * Material 3 pill top bar containing leading icon, title/provider label,
+ * an optional '+' action button, and user avatar.
+ */
+@Composable
+fun ABoxTopPillBar(
+    title: String,
+    onAvatarClick: () -> Unit,
+    modifier: Modifier = Modifier,
+    userName: String? = null,
+    leadingIcon: ImageVector = Icons.Default.LocationOn,
+    onAddClick: (() -> Unit)? = null,
+    addActionContentDescription: String? = "Add",
+    avatarContentDescription: String? = "Account",
+) {
+    Surface(
+        modifier = modifier
+            .fillMaxWidth()
+            .height(56.dp),
+        shape = RoundedCornerShape(28.dp),
+        color = MaterialTheme.colorScheme.surfaceVariant.copy(alpha = 0.6f),
+        tonalElevation = 2.dp,
+    ) {
+        Row(
+            modifier = Modifier
+                .fillMaxWidth()
+                .padding(horizontal = 12.dp),
+            verticalAlignment = Alignment.CenterVertically,
+            horizontalArrangement = Arrangement.spacedBy(8.dp),
+        ) {
+            Icon(
+                imageVector = leadingIcon,
+                contentDescription = null,
+                tint = MaterialTheme.colorScheme.onSurfaceVariant,
+                modifier = Modifier.size(22.dp),
+            )
+
+            Text(
+                text = title,
+                style = MaterialTheme.typography.titleMedium.copy(fontWeight = FontWeight.SemiBold),
+                color = MaterialTheme.colorScheme.onSurface,
+                maxLines = 1,
+                overflow = TextOverflow.Ellipsis,
+                modifier = Modifier.weight(1f),
+            )
+
+            if (onAddClick != null) {
+                IconButton(
+                    onClick = onAddClick,
+                    modifier = Modifier.size(36.dp),
+                ) {
+                    Icon(
+                        imageVector = Icons.Default.Add,
+                        contentDescription = addActionContentDescription,
+                        tint = MaterialTheme.colorScheme.onSurfaceVariant,
+                    )
+                }
+            }
+
+            ABoxUserAvatar(
+                name = userName,
+                onClick = onAvatarClick,
+                size = 36.dp,
+                contentDescription = avatarContentDescription,
+            )
+        }
+    }
+}
+
+/**
+ * ABox standard Material 3 Navigation Bar with pill indicator styling.
+ */
+@Composable
+fun ABoxNavigationBar(
+    modifier: Modifier = Modifier,
+    containerColor: Color = MaterialTheme.colorScheme.surface,
+    content: @Composable RowScope.() -> Unit,
+) {
+    NavigationBar(
+        modifier = modifier,
+        containerColor = containerColor,
+        content = content,
+    )
+}
+
+/**
+ * ABox standard Navigation Bar Item.
+ */
+@Composable
+fun RowScope.ABoxNavigationBarItem(
+    selected: Boolean,
+    onClick: () -> Unit,
+    icon: @Composable () -> Unit,
+    label: @Composable (() -> Unit)? = null,
+    modifier: Modifier = Modifier,
+    enabled: Boolean = true,
+) {
+    NavigationBarItem(
+        selected = selected,
+        onClick = onClick,
+        icon = icon,
+        label = label,
+        modifier = modifier,
+        enabled = enabled,
+        colors = NavigationBarItemDefaults.colors(
+            indicatorColor = MaterialTheme.colorScheme.secondaryContainer,
+            selectedIconColor = MaterialTheme.colorScheme.onSecondaryContainer,
+            unselectedIconColor = MaterialTheme.colorScheme.onSurfaceVariant,
+            selectedTextColor = MaterialTheme.colorScheme.onSurface,
+            unselectedTextColor = MaterialTheme.colorScheme.onSurfaceVariant,
+        ),
+    )
+}