Add multiple features: auth, uploads, queue management, and filters

- Replace email with username for authentication
  - Update User model, schemas, and auth endpoints
  - Update frontend login and register views
  - Add migration to remove email column

- Add multiple track upload support
  - New backend endpoint for bulk upload
  - Frontend multi-file selection with progress
  - Auto-extract metadata from ID3 tags
  - Visual upload progress for each file

- Prevent duplicate tracks in room queue
  - Backend validation for duplicates
  - Visual indication of tracks already in queue
  - Error handling with user feedback

- Add bulk track selection for rooms
  - Multi-select mode with checkboxes
  - Bulk add endpoint with duplicate filtering
  - Selection counter and controls

- Add track filters in room modal
  - Search by title and artist
  - Filter by "My tracks"
  - Filter by "Not in queue"
  - Live filtering with result counter

- Improve Makefile
  - Add build-backend and build-frontend commands
  - Add rebuild-backend and rebuild-frontend commands
  - Add rebuild-clean variants
  - Update migrations to run in Docker

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

frontend/src/views/LoginView.vue

@@ -4,8 +4,8 @@
       <h2>Вход</h2>
       <form @submit.prevent="handleLogin">
         <div class="form-group">
-          <label>Email</label>
-          <input type="email" v-model="email" required />
+          <label>Имя пользователя</label>
+          <input type="text" v-model="username" required />
         </div>
         <div class="form-group">
           <label>Пароль</label>
@@ -31,7 +31,7 @@ import { useAuthStore } from '../stores/auth'
 const router = useRouter()
 const authStore = useAuthStore()
 
-const email = ref('')
+const username = ref('')
 const password = ref('')
 const error = ref('')
 const loading = ref(false)
@@ -41,7 +41,7 @@ async function handleLogin() {
   loading.value = true
 
   try {
-    await authStore.login(email.value, password.value)
+    await authStore.login(username.value, password.value)
     router.push('/')
   } catch (e) {
     error.value = e.response?.data?.detail || 'Ошибка входа'