docs: consolidate and sync docs with current codebase state

- PROJECT_CONTEXT.md: fix effect count (12→18), shader count (27→37),
  update CNN v3 pipeline description, tighten Next Up section
- TODO.md: fix priority numbering, restore GPU PCM synthesis as pending,
  streamline CNN v3 section, consolidate Future items
- doc/SEQUENCE.md: effect count 12→18
- cnn_v3/README.md: phases 1–7→1–9, test count 36→38, add phases 8–9
- cnn_v3/docs/HOWTO.md: fix dataset layout blender/photos→full/simple,
  update test counts 36→38 throughout
- doc/COMPLETED.md: archive FFT/timing/OLA fixes, remove false GPU PCM claim
- src/audio/audio_engine.cc: fix step comment numbering (6→5)
- src/audio/synth.cc: remove stale fractional_pos tempo-scaling comment

handoff(Gemini): docs now accurate — 18 effects, 37 shaders, 38/38 tests,
GPU PCM synthesis back in TODO as pending, CNN v3 dataset layout corrected.

1 files changed, 7 insertions, 7 deletions

diff --git a/PROJECT_CONTEXT.md b/PROJECT_CONTEXT.md
index bffbeb8..d7fc771 100644
--- a/PROJECT_CONTEXT.md
+++ b/PROJECT_CONTEXT.md
@@ -34,21 +34,21 @@
 - **Timing System:** **Beat-based timelines** for musical synchronization. Sequences defined in beats, converted to seconds at runtime. Effects receive both physical time (constant) and beat time (musical). Variable tempo affects audio only. See `doc/BEAT_TIMING.md`.
 - **Workspace system:** Multi-workspace support. Easy switching with `-DDEMO_WORKSPACE=<name>`. Organized structure: `music/`, `weights/`, `obj/`, `shaders/`. Shared common shaders in `src/shaders/`. See `doc/WORKSPACE_SYSTEM.md`.
 - **Audio:** Sample-accurate sync. Zero heap allocations per frame. Variable tempo. OLA-IDCT synthesis (v2 .spec): Hann analysis window, rectangular synthesis, 50% overlap, click-free. V1 (raw DCT-512) preserved for generated notes. .spec files regenerated as v2.
-- **Shaders:** Parameterized effects (UniformHelper, .seq syntax). Beat-synchronized animation support (`beat_time`, `beat_phase`). Modular WGSL composition with ShaderComposer. 27 shared common shaders (math, render, compute). Reusable snippets: `render/scratch_lines`, `render/ntsc_common` (NTSC signal processing, RGB and YIQ input variants via `sample_ntsc_signal` hook), `math/color` (YIQ/NTSC), `math/color_c64` (C64 palette, Bayer dither, border animation).
+- **Shaders:** Parameterized effects (UniformHelper, .seq syntax). Beat-synchronized animation support (`beat_time`, `beat_phase`). Modular WGSL composition with ShaderComposer. 37 shared common shaders (math/, render/, compute/, debug/). Reusable snippets: `render/scratch_lines`, `render/ntsc_common` (NTSC signal processing, RGB and YIQ input variants via `sample_ntsc_signal` hook), `math/color` (YIQ/NTSC), `math/color_c64` (C64 palette, Bayer dither, border animation).
 - **3D:** Hybrid SDF/rasterization with BVH. Binary scene loader. Blender pipeline.
-- **Effects:** CNN post-processing: CNNEffect (v1) and CNNv2Effect operational. CNN v2: sigmoid activation, storage buffer weights (~3.2 KB), 7D static features, dynamic layers. Training stable, convergence validated. **CNN v3 Phases 1–9 complete** + runtime pipeline operational: `GBufferEffect` (MRT raster + sphere impostors + SDF shadow pass) → `GBufDeferredEffect` (albedo×diffuse debug view) wired in `cnn_v3_test` sequence. Two training bugs fixed: dec0 ReLU removed (full [0,1] output range), FiLM MLP loaded from `.bin` at runtime. Parity validated: max_err=4.88e-4. See `cnn_v3/docs/HOWTO.md`.
+- **Effects:** CNN post-processing: CNNEffect (v1) and CNNv2Effect operational. CNN v2: sigmoid activation, storage buffer weights (~3.2 KB), 7D static features, dynamic layers. Training stable, convergence validated. **CNN v3 Phases 1–9 complete** + runtime pipeline operational: `GBufferEffect` (MRT raster + sphere impostors + SDF shadow pass) → `GBufDeferredEffect` (albedo×diffuse) in `cnn_v3_test`; debug sequence adds `CNNv3Effect` → `GBufViewEffect`. Training bugs fixed: dec0 ReLU removed, FiLM MLP loaded from `.bin`. Parity validated: max_err=4.88e-4. See `cnn_v3/docs/HOWTO.md`.
 - **Tools:** CNN test tool operational. Texture readback utility functional. Timeline editor (web-based, beat-aligned, audio playback).
 - **Build:** Asset dependency tracking. Size measurement. Hot-reload (debug-only). WSL (Windows 10) supported: native Linux build and cross-compile to `.exe` via `mingw-w64`.
-- **Sequence:** DAG-based effect routing with explicit node system. Python compiler with topological sort and ping-pong optimization. 12 effects operational (Passthrough, Placeholder, GaussianBlur, Heptagon, Particles, RotatingCube, Hybrid3D, Flash, PeakMeter, Scene1, Scene2, Scratch). Effect times are absolute (seq_compiler adds sequence start offset). See `doc/SEQUENCE.md`.
-- **Testing:** **36/36 passing**.
+- **Sequence:** DAG-based effect routing with explicit node system. Python compiler with topological sort and ping-pong optimization. 18 effects operational (Passthrough, Placeholder, GaussianBlur, Heptagon, Particles, RotatingCube, Hybrid3D, Flash, PeakMeter, Scene1, Scene2, Scratch, Ntsc, NtscYiq, GBufferEffect, CNNv3Effect, GBufDeferredEffect, GBufViewEffect). Effect times are absolute (seq_compiler adds sequence start offset). See `doc/SEQUENCE.md`.
+- **Testing:** **38/38 passing**.
 
 ---
 
 ## Next Up
 
-**Active:** CNN v3 training bugs fixed ✅ — retrain from scratch with more data (≥50 samples). Spectral Brush Editor.
-**Ongoing:** Test infrastructure maintenance (38/38 passing)
-**Future:** CNN v3 training pass, size optimization (64k target)
+**Active:** Spectral Brush Editor (Task #5). CNN v3 data collection + retrain (≥50 samples needed, 11 collected).
+**Ongoing:** Test infrastructure (38/38 passing).
+**Future:** Size optimization (64k target), CNN v3 2D mode, CNN v2 8-bit quantization.
 
 See `TODO.md` for details.