DolphinQt: Fix crash from stale timer event in ToolTipWidget

MathUtil: C++20/23 modernisations

feat(retroachievements): implement achievement notification sounds

Android: Add global hotkeys

Replace manual calculations with std::lerp and std::midpoint

Qt 6.2 has been de facto required since
afa6e26e5de58e942c8e7ef3a02632ccfb851d3d added a call to
QPixmap::deviceIndependentSize which was introduced in that Qt version.

Qt 6.2 was released 5 years ago and we've required 6.2+ for over 2
years, so let's make that requirement explicit in CMakeLists.txt instead
of having an apparently random compile error if anyone happens to try
building with an older Qt version.

LLM generated explaination for the LLM generated commit:

A queued QTimerEvent can be dispatched after the timer was already killed (Qt recycles timer ids), e.g. when a slider is dragged and enter/leave events fire in rapid succession. In that case m_timer_id is empty and dereferencing it in timerEvent() asserts on 'this->_M_is_engaged()' in debug builds, while in release builds it passes a garbage timer id to killTimer().

Only process the event if it matches the timer we are tracking, which also prevents showing a balloon for a stale event.