Integrate DigiRadioFinale DSP program: exclusive source mux, real

Bass Boost1/SPhat1 enhancement blocks

Replaces the 74-parameter ADAU1701 program with the new 224-parameter
SigmaStudio export. The new netlist has no mixer -- MX1 is an
exclusive selector (DC1) passing through exactly one of three stereo
pairs (radio/bluetooth/beep) instead of blending them with independent
gains. core::MixSource/MixerState are gone; core::ActiveSource plus
IDsp::selectSource() replace applyMixer()/setInputVolume() throughout
the driver/service/API stack. AudioProfile.mixer -> activeSource;
the HTTP "mixer" JSON object -> a single "active_source" string.

DC1 turned out to need a raw 32-bit integer (0/1/2), not the 5.23
fixpoint its compiled TYPE_DC1 macro implies -- confirmed live by
writing both encodings and listening for which one actually switched
sources. Documented in Adau1701Driver::selectSource() and
adau1701::paramSourceIndex().

Bass Boost1 and SPhat1 are real ADI algorithm blocks in this revision,
so core::applyEnhancementsToEq() (the old EQ-band-overwrite hack for
bass/stereo enhancement) is deleted; IDsp::setBassBoostLevel()/
setStereoSpreadLevel() scale each block's compiled coefficients toward
identity/unity instead. Confirmed live: Bass Boost audible on real
program content (not a static test tone -- the algorithm is dynamics-
based), Stereo Spread audible but subtle. The EQ "locked" flag from
2026-08-24 (enhancements silently overwriting manually-set bands) no
longer applies to bands 1-5.

A full sweep of all 223 non-DC1 named parameters (writing each back to
its own compiled default) completed with zero failures, confirming the
whole new address space is reachable.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

Software/Firmware/ADAU1701-Firmware/defines.h

@@ -1,8 +1,8 @@
 /*
  * File:           defines.h
  *
- * Created:        Friday, August 7, 2026 3:19:11 AM
- * Description:    DigiRadio IC default download data definitions.
+ * Created:        Tuesday, August 25, 2026 8:11:05 PM
+ * Description:    DigiRadioFinale IC default download data definitions.
  *
  * This software is distributed in the hope that it will be useful,
  * but is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR