Add vue-router, login/setup flow and backend logging

Refactor frontend to route-based navigation with vue-router, add
system setup and login pages with API integration. Add structured
logging, access-log middleware and startup lifecycle to FastAPI
backend.

web/src/views/AppShellRouteView.vue

@@ -0,0 +1,176 @@
+<template>
+  <div class="app">
+    <SidebarRail
+      :nav-items="navItems"
+      :active-view="activeView"
+      @navigate="handleNavigate"
+      @open-chat="handleOpenChat"
+    />
+
+    <main
+      class="main"
+      :class="{
+        'chat-main': activeView === 'chat',
+        'overview-main': activeView === 'overview',
+        'workbench-main': activeView === 'workbench',
+        'requests-main': activeView === 'requests',
+        'approval-main': activeView === 'approval',
+        'policies-main': activeView === 'policies',
+        'audit-main': activeView === 'audit',
+        'employees-main': activeView === 'employees'
+      }"
+    >
+      <TopBar
+        :current-view="topBarView"
+        :search="search"
+        :active-view="activeView"
+        :ranges="ranges"
+        :active-range="activeRange"
+        :custom-range="customRange"
+        @update:search="search = $event"
+        @update:active-range="activeRange = $event"
+        @update:custom-range="customRange = $event"
+        @batch-approve="toast('已批量通过 23 条审批任务。')"
+        @open-chat="handleOpenChat"
+        @new-application="openTravelCreate"
+      />
+
+      <FilterBar
+        v-if="activeView !== 'chat' && activeView !== 'overview' && activeView !== 'workbench' && activeView !== 'requests' && activeView !== 'approval' && activeView !== 'policies' && activeView !== 'audit' && activeView !== 'employees'"
+        :compact="activeView === 'overview'"
+        :filters="filters"
+        :ranges="ranges"
+        :active-range="activeRange"
+        @update:active-range="activeRange = $event"
+      />
+
+      <section
+        class="workarea"
+        :class="{
+          'chat-workarea': activeView === 'chat',
+          'requests-workarea': activeView === 'requests',
+          'approval-workarea': activeView === 'approval',
+          'policies-workarea': activeView === 'policies',
+          'audit-workarea': activeView === 'audit',
+          'employees-workarea': activeView === 'employees'
+        }"
+      >
+        <OverviewView
+          v-if="activeView === 'overview'"
+          :filtered-requests="filteredRequests"
+          @ask="handleOpenChat"
+          @approve="handleApprove"
+          @reject="handleReject"
+        />
+
+        <PersonalWorkbenchView
+          v-else-if="activeView === 'workbench'"
+          @open-assistant="openSmartEntry"
+        />
+
+        <ChatView
+          v-else-if="activeView === 'chat'"
+          :documents="filteredDocuments"
+          :doc-search="docSearch"
+          :messages="messages"
+          :uploaded-files="uploadedFiles"
+          :active-case="activeCase"
+          :quick-prompts="travelPrompts"
+          :draft="draft"
+          :message-list="messageList"
+          @send="sendMessage"
+          @upload="handleUpload"
+          @draft="draft = $event"
+          @select-case="handleOpenChat"
+          @approve-case="toast(`${activeCase?.id || '当前单据'} 已标记为通过。`)"
+          @reject-case="toast(`${activeCase?.id || '当前单据'} 已标记为驳回。`)"
+        />
+
+        <TravelRequestDetailView
+          v-else-if="activeView === 'requests' && detailMode && selectedTravelRequest"
+          :request="selectedTravelRequest"
+          @back-to-requests="closeRequestDetail"
+          @open-assistant="openSmartEntry"
+        />
+
+        <RequestsView
+          v-else-if="activeView === 'requests'"
+          :filtered-requests="filteredRequests"
+          @ask="openRequestDetail"
+          @approve="handleApprove"
+          @reject="handleReject"
+          @create-request="openTravelCreate"
+        />
+
+        <ApprovalCenterView v-else-if="activeView === 'approval'" />
+        <PoliciesView v-else-if="activeView === 'policies'" />
+        <AuditView v-else-if="activeView === 'audit'" />
+        <EmployeeManagementView v-else />
+      </section>
+    </main>
+
+    <TravelReimbursementCreateView
+      v-if="smartEntryOpen"
+      :key="smartEntrySessionId"
+      :initial-prompt="smartEntryContext.prompt"
+      :entry-source="smartEntryContext.source"
+      :request-context="smartEntryContext.request"
+      @close="closeSmartEntry"
+    />
+  </div>
+</template>
+
+<script setup>
+import SidebarRail from '../components/layout/SidebarRail.vue'
+import TopBar from '../components/layout/TopBar.vue'
+import FilterBar from '../components/layout/FilterBar.vue'
+import OverviewView from './OverviewView.vue'
+import PersonalWorkbenchView from './PersonalWorkbenchView.vue'
+import ChatView from './ChatView.vue'
+import TravelReimbursementCreateView from './TravelReimbursementCreateView.vue'
+import TravelRequestDetailView from './TravelRequestDetailView.vue'
+import RequestsView from './RequestsView.vue'
+import ApprovalCenterView from './ApprovalCenterView.vue'
+import PoliciesView from './PoliciesView.vue'
+import AuditView from './AuditView.vue'
+import EmployeeManagementView from './EmployeeManagementView.vue'
+
+import { useAppShell } from '../composables/useAppShell.js'
+
+const {
+  activeCase,
+  activeRange,
+  activeView,
+  closeRequestDetail,
+  closeSmartEntry,
+  customRange,
+  detailMode,
+  docSearch,
+  draft,
+  filteredDocuments,
+  filteredRequests,
+  filters,
+  handleApprove,
+  handleNavigate,
+  handleOpenChat,
+  handleReject,
+  handleUpload,
+  messageList,
+  messages,
+  navItems,
+  openRequestDetail,
+  openSmartEntry,
+  openTravelCreate,
+  ranges,
+  search,
+  selectedTravelRequest,
+  sendMessage,
+  smartEntryContext,
+  smartEntryOpen,
+  smartEntrySessionId,
+  toast,
+  topBarView,
+  travelPrompts,
+  uploadedFiles
+} = useAppShell()
+</script>