refactor: 按 sample_in_harmonyos 多层模块化架构重构工程结构

- 新增 common/ 公共模块：模型、服务、组件、常量
- 新增 features/ 功能模块：graph(星图)、chat(聊天)、settings(设置)、commonbusiness
- 新增 products/phone 产品入口层：EntryAbility + Index + MainPage
- Index.ets 简化为纯路由入口，TabNavigation 移至 MainPage 统一管理
- 更新 build-profile.json5 注册所有新模块
- 迁移原始 entry/ 代码到分层架构，保持功能完整

features/chat/Index.ets

@@ -0,0 +1 @@
+export { ChatPage } from './src/main/ets/pages/ChatPage';

features/chat/build-profile.json5

@@ -0,0 +1,8 @@
+{
+  "apiType": "stageMode",
+  "targets": [
+    {
+      "name": "default"
+    }
+  ]
+}

features/chat/oh-package.json5

@@ -0,0 +1,11 @@
+{
+  "name": "@ohos/chat",
+  "version": "1.0.0",
+  "description": "TrulyMEM chat feature module",
+  "main": "Index.ets",
+  "author": "",
+  "license": "",
+  "dependencies": {
+    "@ohos/common": "file:../../common"
+  }
+}

features/chat/src/main/ets/pages/ChatPage.ets

@@ -0,0 +1,171 @@
+import { GraphDatabase } from '@ohos/common';
+import { GraphMemoryService } from '@ohos/common';
+import { AIAgentService, ChatMessage, AgentResponse } from '@ohos/common';
+
+@Component
+export struct ChatPage {
+    @State messages: ChatMessage[] = [];
+    @State inputText: string = '';
+    @Prop db: GraphDatabase;
+    @State toolCallLog: string = '';
+    @State isThinking: boolean = false;
+    private scrollController: Scroller = new Scroller();
+    private agentService?: AIAgentService;
+
+    async aboutToAppear() {
+        // 初始化图记忆服务和 Agent
+        const memoryService = new GraphMemoryService(this.db);
+        this.agentService = new AIAgentService(memoryService, getContext(this));
+
+        // 加载历史消息（兼容旧数据：无 session_id 时加载全部）
+        const rawHistory = await this.db.getChatHistory(50, this.agentService.getSessionId());
+        if (rawHistory.length === 0) {
+            // 新 session，尝试加载旧消息
+            const legacyHistory = await this.db.getChatHistory(50);
+            this.messages = legacyHistory.map(m => {
+                const msg: ChatMessage = { role: m.role, content: m.content };
+                return msg;
+            });
+        } else {
+            this.messages = rawHistory.map(m => {
+                const msg: ChatMessage = { role: m.role, content: m.content };
+                return msg;
+            });
+        }
+    }
+
+    async sendMessage() {
+        if (!this.inputText.trim() || !this.agentService) return;
+
+        const userMessage: string = this.inputText;
+        this.inputText = '';
+
+        // 添加用户消息
+        await this.db.saveChatMessage('user', userMessage, '', this.agentService.getSessionId());
+        this.messages = [...this.messages, { role: 'user', content: userMessage }];
+
+        // 显示 loading
+        this.isThinking = true;
+        this.toolCallLog = '';
+
+        try {
+            // 通过 Agent 发送消息
+            const agentResponse: AgentResponse = await this.agentService.sendMessage(userMessage);
+
+            // 记录工具调用日志
+            if (agentResponse.toolCalls.length > 0) {
+                const logs: string[] = agentResponse.toolCalls.map(tc => `🛠 ${tc.name}: ${tc.message}`);
+                this.toolCallLog = logs.join('\n');
+            }
+
+            // 保存并显示 AI 回复
+            await this.db.saveChatMessage('assistant', agentResponse.content, this.toolCallLog, this.agentService.getSessionId());
+            this.messages = [...this.messages, { role: 'assistant', content: agentResponse.content }];
+        } catch (err) {
+            console.error('Agent request failed: ' + JSON.stringify(err));
+            this.messages = [...this.messages, { role: 'assistant', content: `⚠️ 请求失败: ${err.message || JSON.stringify(err)}` }];
+        } finally {
+            this.isThinking = false;
+        }
+    }
+
+    build() {
+        Column() {
+            // 聊天列表
+            List() {
+                ForEach(this.messages, (msg: ChatMessage) => {
+                    ListItem() {
+                        Column() {
+                            // 角色标识
+                            Text(msg.role === 'user' ? '🧑 你' : '🤖 AI')
+                                .fontSize(11)
+                                .fontColor(msg.role === 'user' ? '#7C4DFF' : '#999')
+                                .width('100%')
+
+                            // 消息内容
+                            Text(msg.content)
+                                .fontSize(15)
+                                .width('100%')
+                                .margin({ top: 4 })
+                                .fontColor('#FFFFFF')
+                        }
+                        .padding(12)
+                        .backgroundColor(msg.role === 'user' ? 'rgba(124,77,255,0.15)' : 'rgba(245,245,245,0.1)')
+                        .borderRadius(12)
+                        .border({ width: 1, color: msg.role === 'user' ? 'rgba(124,77,255,0.3)' : 'rgba(255,255,255,0.1)' })
+                        .backgroundBlurStyle(BlurStyle.Thin)
+                        .margin({ left: 8, right: 8, bottom: 8 })
+                        .width('100%')
+                        .alignItems(HorizontalAlign.Start)
+                    }
+                })
+
+                // loading 指示
+                if (this.isThinking) {
+                    ListItem() {
+                        Row() {
+                            LoadingProgress()
+                                .width(20)
+                                .height(20)
+                                .margin({ right: 8 })
+                                .color('#7C4DFF')
+                            Text('AI 思考中...')
+                                .fontSize(13)
+                                .fontColor('#7C4DFF')
+                        }
+                        .padding(12)
+                        .backgroundColor('rgba(124,77,255,0.1)')
+                        .borderRadius(12)
+                        .border({ width: 1, color: 'rgba(124,77,255,0.2)' })
+                        .backgroundBlurStyle(BlurStyle.Thin)
+                        .margin({ left: 8, right: 8, bottom: 8 })
+                    }
+                }
+
+                // 工具调用日志
+                if (this.toolCallLog && !this.isThinking) {
+                    ListItem() {
+                        Text(this.toolCallLog)
+                            .fontSize(10)
+                            .fontColor('#FF9800')
+                            .backgroundColor('rgba(255,152,0,0.1)')
+                            .padding(8)
+                            .borderRadius(8)
+                            .border({ width: 1, color: 'rgba(255,152,0,0.2)' })
+                            .backgroundBlurStyle(BlurStyle.Thin)
+                            .margin({ left: 8, right: 8, bottom: 4 })
+                            .lineHeight(16)
+                    }
+                }
+            }
+            .width('100%')
+            .layoutWeight(1)
+            .backgroundColor('rgba(0,0,0,0.1)')
+
+            // 输入区
+            Row() {
+                TextArea({ text: this.inputText, placeholder: '输入消息...' })
+                    .layoutWeight(1)
+                    .onChange((v: string) => { this.inputText = v; })
+                    .height(40)
+                    .backgroundColor('rgba(255,255,255,0.1)')
+                    .borderRadius(8)
+                    .border({ width: 1, color: 'rgba(124,77,255,0.3)' })
+
+                Button('发送')
+                    .enabled(!this.isThinking)
+                    .onClick(() => this.sendMessage())
+                    .backgroundColor('#7C4DFF')
+                    .borderRadius(8)
+            }
+            .width('100%')
+            .padding(8)
+            .backgroundColor('rgba(255,255,255,0.05)')
+            .backgroundBlurStyle(BlurStyle.Regular)
+            .border({ width: 1, color: 'rgba(124,77,255,0.2)', style: BorderStyle.Solid })
+        }
+        .width('100%')
+        .height('100%')
+        .backgroundColor('rgba(26,27,46,0.95)')
+    }
+}