update docs for capability dispatch refactor
- Architecture: add BatteryStatus (0x1000) and SmartShiftEnhanced
(0x2111) to features table, note capability dispatch, fix
Profile::buttons size (8 -> 16)
- HID++ Protocol: add Battery Status and SmartShift Enhanced sections
with function tables and parsing details
- Adding a Device: note that battery/smartshift variants are
auto-detected via capability dispatch tables