Remove model benchmark metadata from dataset

Dataset-card metadata is maintained in README.md frontmatter. The standalone metadata.yaml contains model and benchmark fields, is not a Hugging Face dataset-card metadata document, and is outside the AI Portal model schema contract.

metadata.yaml

@@ -1,43 +0,0 @@
-# Metadata generated by ARM Model Optimization Pipeline
-version: 1.0.0
-task: vision-detection
-created_at: '2026-09-12T01:01:35Z'
-context:
-  model:
-    id: yolo26n
-    base_model_id: yolo26n
-    profile: Arm-Optimized
-    weight_dtype: fp32
-    model_size_mb: 11.287
-    parameter_count: 2572280
-    format: custom-bundle
-  target:
-    name: Raspberry Pi 5
-    hardware_class: Edge Linux
-    cpu_architecture: arm64
-    cpu_model: Cortex-A76
-    cpu_core_count: 4
-    cpu_clock_ghz: 2.4
-    system_memory_gb: 8
-    os: linux
-    os_version: Raspberry Pi OS Bookworm
-  runtime:
-    name: Arm Runtime for YOLO26 on Raspberry Pi 5
-    execution_backend: cpu
-    config:
-      optimisations:
-      - XNNPACK
-  dataset:
-    name: COCO 2017
-    sample_count: 128
-    reference_url: https://cocodataset.org/
-    slice: val2017
-  benchmark:
-    batch_size: 1
-    input_resolution: 640x640
-    num_runs: 50
-    warmup_runs: 10
-accuracy:
-  mAP_50_95_pct: 46.16
-  mAP_50_pct: 49.47
-  mAP_75_pct: 42.84