feat(audio, tools): Add Task #72 and enhance Blender exporter

- Add Task #72 (Audio Pipeline Streamlining) to TODO.md and PROJECT_CONTEXT.md.
- Update blender_export.py to support 'EMPTY' objects for planes and export 'plane_distance'.

1 files changed, 16 insertions, 0 deletions

diff --git a/TODO.md b/TODO.md
index 2400113..72d1b74 100644
--- a/TODO.md
+++ b/TODO.md
@@ -93,6 +93,22 @@ This file tracks prioritized tasks with detailed attack plans.
 
 ---
 
+## Priority 2: Audio Pipeline Streamlining (Task #72)
+
+**Goal**: Optimize the audio pipeline to reduce memory copies and simplify the data flow by using direct additive mixing and deferred clipping.
+
+- [ ] **Phase 1: Direct Additive Mixing**
+  - Modify `Synth` and `Tracker` to accept a target output buffer for direct additive mixing instead of returning isolated voice samples.
+  - Eliminate temporary buffers used for individual voice rendering.
+- [ ] **Phase 2: Float32 Internal Pipeline**
+  - Ensure the entire internal pipeline (synthesis, mixing) maintains full `float32` precision without intermediate clipping.
+- [ ] **Phase 3: Final Clipping & Conversion**
+  - Implement a single, final stage that performs clipping (limiter/clamping) and conversion to `int16` (or other hardware-native formats) just before the audio backend delivery.
+- [ ] **Phase 4: Verification**
+  - Verify audio quality and performance improvements with `test_demo` and existing audio tests.
+
+---
+
 ## Priority 2: 3D System Enhancements (Task #18)
 **Goal:** Establish a pipeline for importing complex 3D scenes to replace hardcoded geometry.