test: add WebSocket integration tests

Add comprehensive WebSocket test coverage:
- TestWebSocketConnection: Basic connection and JWT auth
- TestWebSocketDeviceAuth: Device token authentication
- TestWebSocketProgressBroadcast: Real-time update delivery
- TestWebSocketPingPong: Heartbeat mechanism
- TestWebSocketConnectionLimit: Multiple concurrent connections
- TestWebSocketInvalidToken: Rejection of invalid tokens
- Helper function for test media item creation

Update test helpers to create ConnectionManager for tests.
Tests verify WebSocket connection, authentication, and
real-time progress broadcast functionality.

cmd/server/tests/device_test.go

@@ -119,7 +119,7 @@ func TestListDevices(t *testing.T) {
 	defer ts.Close()
 
 	// Login to get token
-	token := loginTestUser(t, ts)
+	token := loginTestUser(t, ts, db)
 
 	// Create a device directly in the database
 	userID := getTestUserID(t, db)
@@ -164,7 +164,7 @@ func TestUpdateDevice(t *testing.T) {
 	defer ts.Close()
 
 	// Login to get token
-	token := loginTestUser(t, ts)
+	token := loginTestUser(t, ts, db)
 
 	// Create a device directly in the database
 	userID := getTestUserID(t, db)
@@ -220,7 +220,7 @@ func TestDeleteDevice(t *testing.T) {
 	defer ts.Close()
 
 	// Login to get token
-	token := loginTestUser(t, ts)
+	token := loginTestUser(t, ts, db)
 
 	// Create a device directly in the database
 	userID := getTestUserID(t, db)