Wiki: add MIDI, FlexControl, USB Cables, FreeDV docs
New pages:
- MIDI Controller Mapping: Learn mode, 50+ params, profiles, troubleshooting
- FlexControl Tuning Knob: auto-detect, acceleration, button config
- USB Cable Management: CAT/BCD/Bit/Passthrough cable types
Updated pages:
- SpotHub: added FreeDV Reporter tab documentation
- Sidebar: new External Control section
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>