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, 18 insertions, 0 deletions

diff --git a/cnn_v1/shaders/cnn_activation.wgsl b/cnn_v1/shaders/cnn_activation.wgsl
new file mode 100644
index 0000000..4fe771e
--- /dev/null
+++ b/cnn_v1/shaders/cnn_activation.wgsl
@@ -0,0 +1,18 @@
+// CNN activation functions
+// 4 functions: tanh, ReLU, sigmoid, leaky_relu
+
+fn cnn_tanh(x: vec4<f32>) -> vec4<f32> {
+  return tanh(x);
+}
+
+fn cnn_relu(x: vec4<f32>) -> vec4<f32> {
+  return max(vec4<f32>(0.0), x);
+}
+
+fn cnn_sigmoid(x: vec4<f32>) -> vec4<f32> {
+  return 1.0 / (1.0 + exp(-x));
+}
+
+fn cnn_leaky_relu(x: vec4<f32>, alpha: f32) -> vec4<f32> {
+  return max(alpha * x, x);
+}