docs: add detailed integration guide for Steps 5-8

docs: comprehensive README with production results and integration guide

Add feature_schema.json

Add baseline_comparison.json

Add feature_importance.csv

Add eval_metrics.json

Add reranker_v1.txt

Add comprehensive test suite

Add 03_train_lightgbm.py

Add 02_generate_training_triples.py

Add 01_fetch_citation_edges.py

Add synthetic model file

Add pipeline scripts, synthetic model, and test results

Add complete Phase 6 documentation

initial commit