refactor: 前端架构重构 - 提取 CSS 和逻辑到独立模块

前端重构：
- 删除旧的大体积 Vue 组件（HomeView, FileManage, TextSplit 等）
- 删除旧的 composables（useFormatters, useModels, useProjects）
- 新增 core/, page-logic/, pages/, shared/ 模块化目录结构
- 提取 CSS 到 styles/pages/ 目录
- 添加全局样式 variables.css 和 common.css

后端 API 更新：
- chunks: 语义分割 API 增强
- files: 文件处理 API 更新
- models: 模型管理 API 更新
- questions: 问答管理 API 更新
- database: 数据库连接优化
- semantic_embedding: 语义嵌入服务优化

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/src/shared/composables/index.ts

@@ -0,0 +1,6 @@
+/**
+ * Composables - 可复用业务逻辑
+ */
+export * from './useFormatters'
+export * from './useProjects'
+export * from './useModels'

frontend/src/shared/composables/useFormatters.ts

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+/**
+ * 格式化工具函数
+ */
+
+/**
+ * 格式化文件大小
+ */
+export function formatSize(bytes: number): string {
+  if (bytes === 0) return '0 B'
+  const k = 1024
+  const sizes = ['B', 'KB', 'MB', 'GB', 'TB']
+  const i = Math.floor(Math.log(bytes) / Math.log(k))
+  return parseFloat((bytes / Math.pow(k, i)).toFixed(2)) + ' ' + sizes[i]
+}
+
+/**
+ * 格式化日期
+ */
+export function formatDate(date: string | Date): string {
+  const d = new Date(date)
+  const year = d.getFullYear()
+  const month = String(d.getMonth() + 1).padStart(2, '0')
+  const day = String(d.getDate()).padStart(2, '0')
+  return `${year}-${month}-${day}`
+}
+
+/**
+ * 格式化日期时间
+ */
+export function formatDateTime(date: string | Date): string {
+  const d = new Date(date)
+  const year = d.getFullYear()
+  const month = String(d.getMonth() + 1).padStart(2, '0')
+  const day = String(d.getDate()).padStart(2, '0')
+  const hours = String(d.getHours()).padStart(2, '0')
+  const minutes = String(d.getMinutes()).padStart(2, '0')
+  return `${year}-${month}-${day} ${hours}:${minutes}`
+}
+
+/**
+ * 格式化相对时间
+ */
+export function formatRelativeTime(date: string | Date): string {
+  const now = new Date()
+  const d = new Date(date)
+  const diff = now.getTime() - d.getTime()
+
+  const seconds = Math.floor(diff / 1000)
+  const minutes = Math.floor(seconds / 60)
+  const hours = Math.floor(minutes / 60)
+  const days = Math.floor(hours / 24)
+
+  if (days > 7) {
+    return formatDate(date)
+  } else if (days > 0) {
+    return `${days} 天前`
+  } else if (hours > 0) {
+    return `${hours} 小时前`
+  } else if (minutes > 0) {
+    return `${minutes} 分钟前`
+  } else {
+    return '刚刚'
+  }
+}
+
+/**
+ * 格式化数字（千分位）
+ */
+export function formatNumber(num: number): string {
+  return num.toLocaleString('zh-CN')
+}

frontend/src/shared/composables/useModels.ts

@@ -0,0 +1,112 @@
+/**
+ * 模型相关业务逻辑
+ */
+import { ref } from 'vue'
+import { modelApi } from '@/core/api'
+import type { Model } from '@/shared/types'
+import { ElMessage } from 'element-plus'
+
+export function useModels() {
+  const loading = ref(false)
+  const models = ref<Model[]>([])
+
+  /**
+   * 获取模型列表
+   */
+  const fetchModels = async () => {
+    loading.value = true
+    try {
+      const res = await modelApi.list()
+      // 处理两种响应格式
+      if (Array.isArray(res)) {
+        models.value = res
+      } else if (res?.data && Array.isArray(res.data)) {
+        models.value = res.data
+      } else if (res?.results && Array.isArray(res.results)) {
+        models.value = res.results
+      } else {
+        models.value = []
+      }
+    } catch (error: any) {
+      console.error('获取模型列表失败:', error)
+      ElMessage.error('获取模型列表失败')
+      models.value = []
+    } finally {
+      loading.value = false
+    }
+  }
+
+  /**
+   * 添加模型
+   */
+  const addModel = async (data: Partial<Model>): Promise<boolean> => {
+    try {
+      await modelApi.create(data)
+      ElMessage.success('添加成功')
+      await fetchModels()
+      return true
+    } catch (error: any) {
+      console.error('添加模型失败:', error)
+      ElMessage.error(error?.message || '添加模型失败')
+      return false
+    }
+  }
+
+  /**
+   * 更新模型
+   */
+  const updateModel = async (id: number, data: Partial<Model>): Promise<boolean> => {
+    try {
+      await modelApi.update(id, data)
+      ElMessage.success('更新成功')
+      await fetchModels()
+      return true
+    } catch (error: any) {
+      console.error('更新模型失败:', error)
+      ElMessage.error(error?.message || '更新模型失败')
+      return false
+    }
+  }
+
+  /**
+   * 删除模型
+   */
+  const deleteModel = async (id: number): Promise<boolean> => {
+    try {
+      await modelApi.delete(id)
+      ElMessage.success('删除成功')
+      await fetchModels()
+      return true
+    } catch (error: any) {
+      console.error('删除模型失败:', error)
+      ElMessage.error(error?.message || '删除模型失败')
+      return false
+    }
+  }
+
+  /**
+   * 设置默认模型
+   */
+  const setDefaultModel = async (id: number): Promise<boolean> => {
+    try {
+      await modelApi.setDefault(id)
+      ElMessage.success('设置成功')
+      await fetchModels()
+      return true
+    } catch (error: any) {
+      console.error('设置默认模型失败:', error)
+      ElMessage.error(error?.message || '设置默认模型失败')
+      return false
+    }
+  }
+
+  return {
+    loading,
+    models,
+    fetchModels,
+    addModel,
+    updateModel,
+    deleteModel,
+    setDefaultModel
+  }
+}

frontend/src/shared/composables/useProjects.ts

@@ -0,0 +1,98 @@
+/**
+ * 项目相关业务逻辑
+ */
+import { ref } from 'vue'
+import { projectApi } from '@/core/api'
+import type { Project, ProjectCreate } from '@/shared/types'
+import { ElMessage } from 'element-plus'
+
+export function useProjects() {
+  const loading = ref(false)
+  const projects = ref<Project[]>([])
+
+  /**
+   * 获取项目列表
+   */
+  const fetchProjects = async () => {
+    loading.value = true
+    try {
+      const res = await projectApi.list()
+      // 处理两种响应格式
+      if (Array.isArray(res)) {
+        projects.value = res
+      } else if (res?.data && Array.isArray(res.data)) {
+        projects.value = res.data
+      } else if (res?.results && Array.isArray(res.results)) {
+        projects.value = res.results
+      } else {
+        projects.value = []
+      }
+    } catch (error: any) {
+      console.error('获取项目列表失败:', error)
+      ElMessage.error('获取项目列表失败')
+      projects.value = []
+    } finally {
+      loading.value = false
+    }
+  }
+
+  /**
+   * 创建项目
+   */
+  const createProject = async (data: ProjectCreate): Promise<Project | null> => {
+    try {
+      const res = await projectApi.create(data)
+      ElMessage.success('创建成功')
+      await fetchProjects()
+      return res
+    } catch (error: any) {
+      console.error('创建项目失败:', error)
+      ElMessage.error(error?.message || '创建项目失败')
+      return null
+    }
+  }
+
+  /**
+   * 删除项目
+   */
+  const deleteProject = async (id: number): Promise<boolean> => {
+    try {
+      await projectApi.delete(id)
+      ElMessage.success('删除成功')
+      await fetchProjects()
+      return true
+    } catch (error: any) {
+      console.error('删除项目失败:', error)
+      ElMessage.error(error?.message || '删除项目失败')
+      return false
+    }
+  }
+
+  /**
+   * 获取项目详情
+   */
+  const fetchProject = async (id: number): Promise<Project | null> => {
+    try {
+      const res = await projectApi.get(id)
+      if (res && typeof res === 'object' && 'id' in res) {
+        return res as Project
+      } else if (res?.data) {
+        return res.data as Project
+      }
+      return null
+    } catch (error: any) {
+      console.error('获取项目详情失败:', error)
+      ElMessage.error('获取项目详情失败')
+      return null
+    }
+  }
+
+  return {
+    loading,
+    projects,
+    fetchProjects,
+    createProject,
+    deleteProject,
+    fetchProject
+  }
+}