CarSweep: Audio EQ tuning

NEW: Your car's own EQ. Pick your stereo and CarSweep works out the value for every slider it has — shown the way the car shows them. Profiles for Tesla Model 3/Y and VW/Audi MIB3, plus the classic bass/mid/treble set. • EZ Tuning is now four steps and a single sweep instead of six steps and three, and it ends with the numbers for your stereo instead of "turn the bass down a bit". • Band grids: build your own, give it a name, keep several side by side. Presets are copied rather than overwritten, and the editor is a list with proper stepping instead of a text field. • The guided flow now says where to hold the phone — in front of your face, at the height your head normally is. It is the question we get most. • Fixes: the vehicle EQ no longer splits one bass correction across two sliders; equal-height cards on the home screen; the apply button no longer breaks mid-word next to a long grid name.