refactor(cnn): rename cnn_effect to cnn_v1_effect for clarity

Renamed files and classes:
- cnn_effect.{h,cc} → cnn_v1_effect.{h,cc}
- CNNEffect → CNNv1Effect
- CNNEffectParams → CNNv1EffectParams
- CNNLayerParams → CNNv1LayerParams
- CNN_EFFECT.md → CNN_V1_EFFECT.md

Updated all references:
- C++ includes and class usage
- CMake source list
- Timeline (workspaces/main/timeline.seq)
- Test file (test_demo_effects.cc)
- Documentation (CLAUDE.md, PROJECT_CONTEXT.md, READMEs)

Tests: 34/34 passing (100%)

1 files changed, 2 insertions, 2 deletions

diff --git a/src/tests/gpu/test_demo_effects.cc b/src/tests/gpu/test_demo_effects.cc
index ec78c10..8726e55 100644
--- a/src/tests/gpu/test_demo_effects.cc
+++ b/src/tests/gpu/test_demo_effects.cc
@@ -12,7 +12,7 @@
 
 #include "../common/effect_test_helpers.h"
 #include "../common/webgpu_test_fixture.h"
-#include "effects/cnn_effect.h"
+#include "../../../cnn_v1/src/cnn_v1_effect.h"
 #include "gpu/demo_effects.h"
 #include "gpu/effect.h"
 #include <cassert>
@@ -89,7 +89,7 @@ static void test_post_process_effects() {
       {"ThemeModulationEffect",
        std::make_shared<ThemeModulationEffect>(fixture.ctx())},
       {"VignetteEffect", std::make_shared<VignetteEffect>(fixture.ctx())},
-      {"CNNEffect", std::make_shared<CNNEffect>(fixture.ctx())},
+      {"CNNv1Effect", std::make_shared<CNNv1Effect>(fixture.ctx())},
       {"CNNv2Effect", std::make_shared<CNNv2Effect>(fixture.ctx())},
   };