[PaoloPangallo]

Summary

• Adds a concise, Markdown-documented 22-cell notebook as the primary read-only analysis path.
• Extracts reusable COCO, PCA/axial geometry, mask matching, and optional inference utilities.
• Adds opt-in (disabled by default) training and inference, with separate requirements.
• Corrects the COCO AR index labelling (stats[6] = AR@1, [7] = AR@10, [8] = AR@100).
• Changes confidence-threshold tuning to validation only, with the selected threshold frozen for test.
• Leaves Segmentation.ipynb and its exploratory SAM/RANSAC/DeepLSD experiments unchanged.

Verification

• Locally assembled equivalent: 7 synthetic/static tests passed; 10 code cells executed in no-dataset mode.
• Repository copy: GitHub read-back verified JSON has 22 cells, 10 code cells and zero stored outputs.
• Not run: real dataset/GPU inference, training or numeric metric reproduction because matching dataset, predictions and resolved weights were unavailable.

Review notes

The README historical AP50/AR/angular results are not claimed as reproduced. Compare model versions and dataset snapshots before rerunning. See REFACTOR_AUDIT.md and README_REFACTOR.md.