Fix metrics: consistent bi-encoder baseline (0.698 MRR)

README.md

@@ -74,9 +74,9 @@ When combined with RadLIT-BiEncoder:
 
 | Configuration | MRR | Improvement |
 |---------------|-----|-------------|
-| Bi-encoder only | 0.703 | baseline |
-| + Cross-encoder reranking | 0.741 | +5.4% |
-| + Calibrated fusion (RadLITE) | **0.829** | **+17.9%** |
+| Bi-encoder only | 0.698 | baseline |
+| + Cross-encoder reranking | 0.782 | +12.0% |
+| + BM25 fusion (RadLITE) | **0.829** | **+18.8%** |
 
 ### Performance on Complex Queries