fix(diffsinger): keep rest-note midi/pitch values instead of zeroing

Rest notes had note_midi and ph_midi forced to 0. In all-rest segments the
nearest-fill pass has no non-rest neighbor to overwrite them, so models
received zero midi and either predicted degenerate durations/pitch or failed
outright. Always seed from the original key (pitch also adds cents/100) and
keep isRest masks + nearest fill untouched.

Author: wolfgitpr

plugins/diffsinger/duration/DurationInference.cpp

@@ -71,7 +71,7 @@ namespace srt::svs {
                 const auto &note = word.notes[idx];
                 const auto rest = static_cast<uint8_t>(note.is_rest);
                 isRest.push_back(rest);
-                phMidi.push_back(rest ? 0 : note.key);
+                phMidi.push_back(note.key);
             }
 
             if (!ds::infer::inferutil::fillRestMidiWithNearestInPlace<int64_t>(phMidi, isRest)) {

plugins/diffsinger/pitch/PitchInference.cpp

@@ -268,9 +268,8 @@ namespace srt::svs {
         for (const auto &word : pitchInput->words) {
             for (const auto &note : word.notes) {
                 noteRest.emplace_back(note.is_rest ? 1 : 0);
-                noteMidi.emplace_back(note.is_rest ? 0
-                                                   : (static_cast<float>(note.key) +
-                                                      static_cast<float>(note.cents) / 100.0f));
+                noteMidi.emplace_back(static_cast<float>(note.key) +
+                                      static_cast<float>(note.cents) / 100.0f);
                 int64_t noteDurPrevFrames = std::llround(noteDurSum / frameWidth);
                 noteDurSum += note.duration;
                 int64_t noteDurCurrFrames = std::llround(noteDurSum / frameWidth);