Qt lab — dynamic widget collection with signals/slots (lab6).
Write a class that holds a resizable collection of widgets. A button dynamically adds new widgets to the collection; another button connects all widgets to each other via signals/slots so that interacting with one affects the others.
Constraints: widgets are NOT auto-connected on creation; connections are established on demand via QMetaObject (no dynamic_cast/static_cast). Connected widget types: QLabel, QSlider, QScrollBar, QSpinBox.
Files: widgetcollection.h/.cpp — collection class; mainwindow.h/.cpp/.ui — main window.