feat: remove nginx, add projects/milestones/notifications pages

- Dockerfile: replace nginx with serve for static files
- Fix auth endpoint: /auth/login → /auth/token
- Add ProjectsPage, ProjectDetailPage
- Add MilestonesPage, MilestoneDetailPage with progress bar
- Add NotificationsPage with unread count
- Sidebar: add milestones/notifications nav, live unread badge
- API: configurable VITE_API_BASE for host nginx proxy
- Types: add Milestone, MilestoneProgress, Notification, ProjectMember

src/services/api.ts

@@ -1,7 +1,7 @@
 import axios from 'axios'
 
 const api = axios.create({
-  baseURL: '/api',
+  baseURL: import.meta.env.VITE_API_BASE || '/api',
 })
 
 api.interceptors.request.use((config) => {
@@ -17,7 +17,9 @@ api.interceptors.response.use(
   (err) => {
     if (err.response?.status === 401) {
       localStorage.removeItem('token')
-      window.location.href = '/login'
+      if (window.location.pathname !== '/login') {
+        window.location.href = '/login'
+      }
     }
     return Promise.reject(err)
   }