feat: patch dump/load + preset management over USB MIDI

[joak0068]

Lets Propagator drive the on-device QSPI presets it previously couldn't reach. New SysEx commands (docs/MIDI_PROTOCOL.md §3-4):
0x10 / 0x50 full live patch dump (device->editor, so a recall or a
hardware tweak syncs the UI)
0x11 patch load (set all live values)
0x20/0x21/0x22 save / recall / list the active mode's 3 QSPI slots
0x52 slot occupancy + active slot
A Program Change is an alias for recall. The slots are the same ones the
Footswitch-2 gesture uses; the hooks reuse the existing PresetCapture/Apply
glue and run from the main loop via PumpMidi. Patch values are 7-bit to
stay under libDaisy's 128-byte inbound SysEx buffer.

What this changes

Patch dump/load + preset management over USB MIDI (docs/MIDI_PROTOCOL.md §3-4).
New SysEx commands let Propagator drive the on-device presets it previously couldn't see:
0x10/0x50 dump the full live patch (device → editor, so a hardware tweak or a recall
syncs the UI), 0x11 loads a patch, and 0x20/0x21/0x22 save / recall / list the three
QSPI slots of the active mode, with 0x52 reporting slot occupancy + the active slot. A
Program Change is an alias for recall. The slots are the same ones the Footswitch-2 gesture
uses; the commands reuse the existing capture/apply glue. Patch values are 7-bit to stay
under libDaisy's 128-byte inbound SysEx buffer.

Checklist

• New tunable values live in src/config/params.h
• If a control changed, updated docs/MIDI_PROTOCOL.md and the params::midi map
• Tested on hardware (Daisy Seed + Hothouse) — describe below, or note if untested