cnn_test: --weights now overrides layer config from .bin file

When using --weights option:
- Layer count and kernel sizes loaded from binary header
- Warnings shown if --layers or --cnn-version specified
- Help text clarifies precedence order
- Binary weights always take precedence over CLI args

Updated documentation:
- doc/CNN_TEST_TOOL.md: Usage examples with --weights
- doc/HOWTO.md: Runtime weight loading example

handoff(Claude): cnn_test --weights config override

1 files changed, 5 insertions, 0 deletions

diff --git a/doc/HOWTO.md b/doc/HOWTO.md
index 85ce801..3746d65 100644
--- a/doc/HOWTO.md
+++ b/doc/HOWTO.md
@@ -268,6 +268,9 @@ See `doc/ASSET_SYSTEM.md` and `doc/WORKSPACE_SYSTEM.md`.
 # CNN v2 (recommended, fully functional)
 ./build/cnn_test input.png output.png --cnn-version 2
 
+# CNN v2 with runtime weight loading (loads layer config from .bin)
+./build/cnn_test input.png output.png --weights checkpoints/checkpoint_epoch_100.pth.bin
+
 # CNN v1 (produces incorrect output, debug only)
 ./build/cnn_test input.png output.png --cnn-version 1
 
@@ -282,6 +285,8 @@ See `doc/ASSET_SYSTEM.md` and `doc/WORKSPACE_SYSTEM.md`.
 - **CNN v2:** ✅ Fully functional, matches CNNv2Effect
 - **CNN v1:** ⚠️ Produces incorrect output, use CNNEffect in demo for validation
 
+**Note:** `--weights` loads layer count and kernel sizes from the binary file, overriding `--layers` and forcing CNN v2.
+
 See `doc/CNN_TEST_TOOL.md` for full documentation.
 
 ---