Fix Memory-management issues from TODO.md

- JaySynth's destructor now uses delete[] to match every new T[n]
  allocation (m_pVoices, pPer_voice_controls, pCurrNoteInfos,
  humanize_voice_param[i], ppHumanizedSliders[i], m_ppAudioThread,
  m_ppEventAudioThreadRdy), fixing undefined behavior from the
  mismatched scalar delete.
- Found and fixed the same new[]/delete mismatch pattern via
  ScopedPointer in PluginProcessor.cpp: ScopedPointer always calls
  scalar delete (per JUCE's own doc comment "do not give it an array
  to hold!"), so ScopedPointer<char> holding a new char[...] in
  setStateInformation/setCurrentProgramStateInformation had the same
  bug. Replaced both with HeapBlock<char>, JUCE's array-owning,
  malloc/free-backed smart pointer.
- Added a shared SynthCheckAlloc() helper (synth_defs.h/synth_debug.c)
  that aborts with a diagnostic instead of returning NULL, and wrapped
  all 24 malloc call sites across the C DSP core (env.c, lfo.c, vcf.c,
  vco.c, blit.c, wavetable.c, voice.c, param_scale.c). All are
  one-time init/bufsize-change calls, never in the per-block render
  path, so this adds no real-time-thread overhead.

Verified with clean debug and release builds (no new warnings/errors)
and a full link.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_011dhtwRLARk4eiPngcQykLJ

src/plug/JaySynth.cpp

@@ -158,7 +158,7 @@ JaySynth::~JaySynth()
 	{
 		delete(m_ppAudioThread[i]);
 	}
-	delete(m_ppAudioThread);
+	delete[] m_ppAudioThread;
 
 	SynthDebug("delete params\n");
 	paramInfoFree(&pb_range[0]);
@@ -171,25 +171,25 @@ JaySynth::~JaySynth()
 		{
 			paramInfoFree(&humanize_voice_param[i][j]);
 		}
-		delete (humanize_voice_param[i]);
-		delete (ppHumanizedSliders[i]);
+		delete[] humanize_voice_param[i];
+		delete[] ppHumanizedSliders[i];
 	}
-	delete (humanize_voice_param);
-	delete (ppHumanizedSliders);
+	delete[] humanize_voice_param;
+	delete[] ppHumanizedSliders;
 
 	for (i = max_num_voices; --i >= 0;)
 	{
 		removeVoice(i);
 	}
 
-	delete (pPer_voice_controls);
-	delete (pCurrNoteInfos);
-	delete (m_pVoices);
+	delete[] pPer_voice_controls;
+	delete[] pCurrNoteInfos;
+	delete[] m_pVoices;
 	for (i=0; i < m_num_audiothreads; i++)
 	{
 		delete (m_ppEventAudioThreadRdy[i]);
 	}
-	delete(m_ppEventAudioThreadRdy);
+	delete[] m_ppEventAudioThreadRdy;
 
 
 }