feat: data export — CSV export for tasks, users, activities

- Backend: GET /api/export/{tasks,users,activities}?month=YYYY-MM
- Frontend: Export panel on Reports page (CEO/CTO/Manager only)
- API: apiExportCsv helper for browser download

src/App.tsx

@@ -240,7 +240,7 @@ export default function App() {
               filterUser={null} searchQuery={searchQuery} onToggleDone={handleToggleDone} users={users} />
           )}
           {displayPage === 'teamtasks' && <TeamTasksPage tasks={tasks} currentUser={currentUser} users={users} />}
-          {displayPage === 'reports' && <ReportsPage tasks={tasks} users={users} />}
+          {displayPage === 'reports' && <ReportsPage tasks={tasks} users={users} currentUser={currentUser} />}
           {displayPage === 'members' && <MembersPage tasks={tasks} users={users} currentUser={currentUser} onAddUser={handleAddUser} onDeleteUser={handleDeleteUser} />}
         </div>
       </div>

src/Reports.tsx

@@ -1,5 +1,7 @@
+import { useState } from 'react';
 import type { Task, User } from './data';
 import { STATUS_COLORS, PRIORITY_COLORS } from './data';
+import { apiExportCsv } from './api';
 import { BarChart, Bar, PieChart, Pie, Cell, LineChart, Line, XAxis, YAxis, Tooltip, ResponsiveContainer, Legend } from 'recharts';
 
 const tooltipStyle = {
@@ -8,7 +10,12 @@ const tooltipStyle = {
     labelStyle: { color: '#94a3b8' },
 };
 
-export function ReportsPage({ tasks, users }: { tasks: Task[]; users: User[] }) {
+export function ReportsPage({ tasks, users, currentUser }: { tasks: Task[]; users: User[]; currentUser: User }) {
+    const [exportType, setExportType] = useState<'tasks' | 'users' | 'activities'>('tasks');
+    const [exportMonth, setExportMonth] = useState('');
+    const [exporting, setExporting] = useState(false);
+
+    const canExport = ['ceo', 'cto', 'manager'].includes(currentUser.role);
     const total = tasks.length;
     const completed = tasks.filter(t => t.status === 'done').length;
     const overdue = tasks.filter(t => new Date(t.dueDate + 'T00:00:00') < new Date() && t.status !== 'done').length;
@@ -113,6 +120,44 @@ export function ReportsPage({ tasks, users }: { tasks: Task[]; users: User[] })
                     </ResponsiveContainer>
                 </div>
             </div>
+
+            {canExport && (
+                <div className="chart-card" style={{ marginTop: 24 }}>
+                    <div className="chart-card-title" style={{ display: 'flex', alignItems: 'center', gap: 8 }}>
+                        <span>📥</span> Export Data
+                    </div>
+                    <div style={{ display: 'flex', gap: 12, alignItems: 'flex-end', flexWrap: 'wrap' }}>
+                        <div className="modal-field" style={{ margin: 0 }}>
+                            <label style={{ fontSize: 11, color: '#94a3b8', display: 'block', marginBottom: 4 }}>Dataset</label>
+                            <select className="modal-input" style={{ width: 160 }} value={exportType} onChange={e => setExportType(e.target.value as 'tasks' | 'users' | 'activities')}>
+                                <option value="tasks">Tasks</option>
+                                <option value="users">Users & Workload</option>
+                                <option value="activities">Activity Log</option>
+                            </select>
+                        </div>
+                        <div className="modal-field" style={{ margin: 0 }}>
+                            <label style={{ fontSize: 11, color: '#94a3b8', display: 'block', marginBottom: 4 }}>Month (optional)</label>
+                            <input className="modal-input" type="month" style={{ width: 160 }} value={exportMonth} onChange={e => setExportMonth(e.target.value)} />
+                        </div>
+                        <button
+                            className="btn-primary"
+                            disabled={exporting}
+                            onClick={async () => {
+                                setExporting(true);
+                                try {
+                                    await apiExportCsv(exportType, exportMonth || undefined);
+                                } catch (err) {
+                                    console.error('Export failed:', err);
+                                } finally {
+                                    setExporting(false);
+                                }
+                            }}
+                        >
+                            {exporting ? 'Exporting...' : '⬇ Download CSV'}
+                        </button>
+                    </div>
+                </div>
+            )}
         </div>
     );
 }

src/api.ts

@@ -48,6 +48,21 @@ export async function apiDeleteUser(id: string) {
     });
 }
 
+export async function apiExportCsv(type: 'tasks' | 'users' | 'activities', month?: string) {
+    const params = month ? `?month=${month}` : '';
+    const res = await fetch(`${API_BASE}/export/${type}${params}`);
+    if (!res.ok) throw new Error('Export failed');
+    const blob = await res.blob();
+    const url = URL.createObjectURL(blob);
+    const a = document.createElement('a');
+    a.href = url;
+    a.download = month ? `${type}_${month}.csv` : `${type}_all.csv`;
+    document.body.appendChild(a);
+    a.click();
+    document.body.removeChild(a);
+    URL.revokeObjectURL(url);
+}
+
 // Tasks
 export async function apiFetchTasks() {
     return request('/tasks');