Migrate to a smaller UI host: Electron is a pig-and-a-half

[kevinfrei]

Pick one of:

• Tauri: Probably have to learn Rust. Maybe would be interesting? The url handler didn't like flac audio last time I checked (and they were unwilling to add a "trust me" bit because Rustaceans want to live at the forefront of the security arms race, I guess...)
• Neutralino: I'd probably just fork the project, because their build system is a fluster-cluck, and writing C++ doesn't scare me in the least (I've already got a CMake fork working...)
• WebView: This is super bare-bones (even lighter than Neutralino). But Neutralino also has a less-than-stellar programming model, so maybe this would be a better starting point. The build is bad (build.sh: wtf, programming people?) and I'd probably have to figure out packaging...
• Fork and strip Electron: This is daunting, but much of the cruft (outside the packaging size) is related to security stuff that I don't care about for something that isn't hostly arbitrary web content. I suspect the other efforts in this space would be faster to complete...

[kevinfrei]

The biggest challenge is the ability to intercept the protocol for an audio tag. Tauri supports it, but won't let me manually set the mime-type, and doesn't parse a flac file, so it's stuck. Not sure about the other two...