feat(frontend): layout header + drawer + router (9 routes)

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

frontend/src/api/tasks.js

@@ -0,0 +1,8 @@
+import client from './client';
+export const tasksApi = {
+    list: (params) => client.get('/api/tasks', { params }).then(r => r.data),
+    get: (id) => client.get(`/api/tasks/${id}`).then(r => r.data),
+    create: (t) => client.post('/api/tasks', t).then(r => r.data),
+    update: (id, t) => client.put(`/api/tasks/${id}`, t).then(r => r.data),
+    delete: (id) => client.delete(`/api/tasks/${id}`),
+};