Dinghy 0.4

Dinghy 0.4 brings OberVave's platform over to the base:

• MIDI: the FM-1's TRS MIDI IN next to USB in one queue (midi_get returns 1 for USB, 2 for TRS); clock, start, stop and continue reach the app. The demo shows an incoming clock's tempo, blinks PLAY on the beat, and PRESETS sets a MIDI channel (OMNI or 1-16) for in and out.
• Storage: settings up to 4 KB, 8 blobs of 4 KB, 8 slots of 16 KB, each with a CRC (store.h).
• LCD_IDLE: the app reads MIDI while the screen's DMA runs, so notes don't wait for a redraw.
• The update loader's screen (FM-1): your name in your colour, a progress bar, what to do.
• SMK-37 (Pro, Elite, MKE-P37): ./build.sh --board smk37 [--model elite|mke], the same app with velocity, outer keys, 16 coloured pads, faders and the pitch wheel (genkigenki's board layer).
• Tests and CI: tests/run_tests.sh (host app, flash maps, update path, loader, installer); a tag builds, tests and releases with a build attestation.

Tested on the host and in CI. The platform code runs on the device in OberVave; Dinghy 0.4 itself has not been tried on an FM-1 or SMK-37 yet.

Packages: dinghy-0.4.fwsc (FM-1, FM-1_994), dinghy-0.4-smk37.fwsc (SMK-37 Pro), -smk37-elite, -smk37-mke.