Retire MPE scaffold; stand up reaper_reasampler pure-core skeleton

Rename CMake project/module to reaper_reasampler, delete mpe_model/mpe_view,
add minimal pure bank_model lib + placeholder CTest. main.cpp loads, logs to
console, keeps the action-registration seam commented with the forever-stable
CEREBELLUM_REASAMPLER_ action-id prefix.

src/bank_model.cpp

@@ -0,0 +1,10 @@
+#include "bank_model.h"
+
+namespace reasampler {
+
+int bankModelVersion()
+{
+    return 1;
+}
+
+} // namespace reasampler