archive(cnn): move CNN v1 to cnn_v1/ subdirectory

Consolidate CNN v1 (CNNEffect) into dedicated directory:
- C++ effect: src/effects → cnn_v1/src/
- Shaders: workspaces/main/shaders/cnn → cnn_v1/shaders/
- Training: training/train_cnn.py → cnn_v1/training/
- Docs: doc/CNN*.md → cnn_v1/docs/

Updated all references:
- CMake source list
- C++ includes (relative paths: ../../cnn_v1/src/)
- Asset paths (../../cnn_v1/shaders/)
- Documentation cross-references

CNN v1 remains active in timeline. For new work, use CNN v2 with
enhanced features (7D static, storage buffer, sigmoid activation).

Tests: 34/34 passing (100%)

1 files changed, 53 insertions, 0 deletions

diff --git a/cnn_v1/shaders/cnn_conv7x7.wgsl b/cnn_v1/shaders/cnn_conv7x7.wgsl
new file mode 100644
index 0000000..e68d644
--- /dev/null
+++ b/cnn_v1/shaders/cnn_conv7x7.wgsl
@@ -0,0 +1,53 @@
+// 7x7 convolution with 49 samples
+// Applies mat4 weights per sample
+
+fn cnn_conv7x7(
+  tex: texture_2d<f32>,
+  samp: sampler,
+  uv: vec2<f32>,
+  resolution: vec2<f32>,
+  weights: array<mat4x4<f32>, 49>,
+  bias: vec4<f32>
+) -> vec4<f32> {
+  let step = 1.0 / resolution;
+  var sum = bias;
+  var idx = 0;
+
+  for (var dy = -3; dy <= 3; dy++) {
+    for (var dx = -3; dx <= 3; dx++) {
+      let offset = vec2<f32>(f32(dx), f32(dy)) * step;
+      let sample = textureSample(tex, samp, uv + offset);
+      sum += weights[idx] * sample;
+      idx++;
+    }
+  }
+
+  return sum;
+}
+
+fn cnn_conv7x7_with_coord(
+  tex: texture_2d<f32>,
+  samp: sampler,
+  uv: vec2<f32>,
+  resolution: vec2<f32>,
+  rgba_weights: array<mat4x4<f32>, 49>,
+  coord_weights: mat2x4<f32>,
+  bias: vec4<f32>
+) -> vec4<f32> {
+  let step = 1.0 / resolution;
+  var sum = bias;
+
+  sum += coord_weights * uv;
+
+  var idx = 0;
+  for (var dy = -3; dy <= 3; dy++) {
+    for (var dx = -3; dx <= 3; dx++) {
+      let offset = vec2<f32>(f32(dx), f32(dy)) * step;
+      let rgba = textureSample(tex, samp, uv + offset);
+      sum += rgba_weights[idx] * rgba;
+      idx++;
+    }
+  }
+
+  return sum;
+}