FreqTrace v0.4.0

Signed with an Apple Development certificate (not notarized). Opens cleanly on Macs that trust this developer; generally blocked on others.
On an unrecognized Mac, first launch: right-click FreqTrace.app > Open > Open.

What's Changed

• Uppercase the Octave/Decade toggle to match the view toggle by @vk0eppel in #50
• Show full raw resolution at low frequencies in RTA None mode by @vk0eppel in #52
• Fix control hit targets and align the graph cluster labels by @vk0eppel in #53
• Combined waterfall + RTA overlay via independent layers (#45) by @vk0eppel in #55
• Version bump for v0.4.0 by @vk0eppel in #56

Full Changelog: v0.3.1...v0.4.0