Add temporary model placeholder

Add a clearly labelled text placeholder at the model filename required by the current catalogue metadata contract. No converted weights are distributed.

metadata.yaml

@@ -5,7 +5,7 @@ title: YOLO26n for Raspberry Pi 5
 description: An Arm-optimized YOLO26n object-detection model generated locally for CPU inference on Raspberry Pi 5 using the project-specific Arm Runtime.
 family_name: YOLO26
 id: Arm/Arm-Runtime-for-YOLO26-on-Raspberry-Pi-5
-filename: build/arm_yolo26n_pi5_model/model/model.bin
+filename: runtime/arm_yolo26n_pi5_model/model/model.bin
 base_model_id: yolo26n
 vendor: Ultralytics
 base_model_url: https://docs.ultralytics.com/models/yolo26/

model/README.md

@@ -5,3 +5,5 @@ To export another compatible YOLO26n model, place its checkpoint here as
 
 No PyTorch checkpoint is distributed in this repository.
 Converted model weights are also generated locally and are not distributed.
+The packaged `model.bin` is a text placeholder for catalogue integration, not
+a runnable model artifact.

runtime/arm_yolo26n_pi5_model/model/model.bin

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:6b6fb792a8f6a53735e43803de433aa8aca4518eb7a2c40b6b81d9ab9e73ebba
+size 190