refactor(audio): Finalize audio sync, update docs, and clean up test artifacts

- Implemented sample-accurate audio-visual synchronization by using the hardware audio clock as the master time source.
- Ensured tracker updates and visual rendering are slaved to the stable audio clock.
- Corrected  to accept and use delta time for sample-accurate event scheduling.
- Updated all relevant tests (, , , , ) to use the new delta time parameter.
- Added  function.
- Marked Task #71 as completed in .
- Updated  to reflect the audio system's current status.
- Created a handoff document: .
- Removed temporary peak log files (, ).

1 files changed, 12 insertions, 12 deletions

diff --git a/src/tests/test_variable_tempo.cc b/src/tests/test_variable_tempo.cc
index e27e7d6..4fc81e3 100644
--- a/src/tests/test_variable_tempo.cc
+++ b/src/tests/test_variable_tempo.cc
@@ -44,7 +44,7 @@ void test_basic_tempo_scaling() {
     for (int i = 0; i < 10; ++i) {
       float dt = 0.1f; // 100ms physical steps
       music_time += dt * tempo_scale;
-      engine.update(music_time);
+      engine.update(music_time, dt * tempo_scale);
     }
 
     // After 1 second physical time at 1.0x tempo:
@@ -64,7 +64,7 @@ void test_basic_tempo_scaling() {
     for (int i = 0; i < 10; ++i) {
       float dt = 0.1f;
       music_time += dt * tempo_scale;
-      engine.update(music_time);
+      engine.update(music_time, dt * tempo_scale);
     }
 
     // After 1 second physical time at 2.0x tempo:
@@ -84,7 +84,7 @@ void test_basic_tempo_scaling() {
     for (int i = 0; i < 10; ++i) {
       float dt = 0.1f;
       music_time += dt * tempo_scale;
-      engine.update(music_time);
+      engine.update(music_time, dt * tempo_scale);
     }
 
     // After 1 second physical time at 0.5x tempo:
@@ -123,7 +123,7 @@ void test_2x_speedup_reset_trick() {
     tempo_scale = fminf(tempo_scale, 2.0f);
 
     music_time += dt * tempo_scale;
-    engine.update(music_time);
+    engine.update(music_time, dt * tempo_scale);
   }
 
   printf("    After 5s physical: tempo=%.2fx, music_time=%.3f\n", tempo_scale,
@@ -142,7 +142,7 @@ void test_2x_speedup_reset_trick() {
   for (int i = 0; i < 20; ++i) {
     physical_time += dt;
     music_time += dt * tempo_scale;
-    engine.update(music_time);
+    engine.update(music_time, dt * tempo_scale);
   }
 
   printf("    After reset + 2s: tempo=%.2fx, music_time=%.3f\n", tempo_scale,
@@ -183,7 +183,7 @@ void test_2x_slowdown_reset_trick() {
     tempo_scale = fmaxf(tempo_scale, 0.5f);
 
     music_time += dt * tempo_scale;
-    engine.update(music_time);
+    engine.update(music_time, dt * tempo_scale);
   }
 
   printf("    After 5s physical: tempo=%.2fx, music_time=%.3f\n", tempo_scale,
@@ -201,7 +201,7 @@ void test_2x_slowdown_reset_trick() {
   for (int i = 0; i < 20; ++i) {
     physical_time += dt;
     music_time += dt * tempo_scale;
-    engine.update(music_time);
+    engine.update(music_time, dt * tempo_scale);
   }
 
   printf("    After reset + 2s: tempo=%.2fx, music_time=%.3f\n", tempo_scale,
@@ -235,7 +235,7 @@ void test_pattern_density_swap() {
   printf("  Phase 1: Sparse pattern, normal tempo\n");
   for (float t = 0.0f; t < 3.0f; t += 0.1f) {
     music_time += 0.1f * tempo_scale;
-    engine.update(music_time);
+    engine.update(music_time, 0.1f * tempo_scale);
   }
   const size_t sparse_events = backend.get_events().size();
   printf("    Events during sparse phase: %zu\n", sparse_events);
@@ -245,7 +245,7 @@ void test_pattern_density_swap() {
   tempo_scale = 2.0f;
   for (float t = 0.0f; t < 2.0f; t += 0.1f) {
     music_time += 0.1f * tempo_scale;
-    engine.update(music_time);
+    engine.update(music_time, 0.1f * tempo_scale);
   }
   const size_t events_at_2x = backend.get_events().size() - sparse_events;
   printf("    Additional events during 2.0x: %zu\n", events_at_2x);
@@ -260,7 +260,7 @@ void test_pattern_density_swap() {
   const size_t events_before_reset_phase = backend.get_events().size();
   for (float t = 0.0f; t < 2.0f; t += 0.1f) {
     music_time += 0.1f * tempo_scale;
-    engine.update(music_time);
+    engine.update(music_time, 0.1f * tempo_scale);
   }
   const size_t events_after_reset = backend.get_events().size();
 
@@ -304,7 +304,7 @@ void test_continuous_acceleration() {
     tempo_scale = fmaxf(min_tempo, fminf(max_tempo, tempo_scale));
 
     music_time += dt * tempo_scale;
-    engine.update(music_time);
+    engine.update(music_time, dt * tempo_scale);
 
     // Log at key points
     if (i % 50 == 0) {
@@ -354,7 +354,7 @@ void test_oscillating_tempo() {
     float tempo_scale = 1.0f + 0.2f * sinf(physical_time * 2.0f);
 
     music_time += dt * tempo_scale;
-    engine.update(music_time);
+    engine.update(music_time, dt * tempo_scale);
 
     if (i % 25 == 0) {
       printf("    t=%.2fs: tempo=%.3fx, music_time=%.3f\n", physical_time,