fix: deduplicate gene_symbol in scoring to prevent non-canonical ID inflation

gene_universe contains 1,539 gene_symbols mapping to multiple Ensembl IDs
(3,033 excess). Non-canonical IDs lack data in some evidence tables, causing
weighted_sum/available_weight to inflate their composite scores.

Fix: after scoring SQL, keep one row per gene_symbol with the most
evidence_count (tiebreak by composite_score DESC). 22,604 → 19,555 genes.

Results: HIGH 82→4, all top 20 now have 5-6 layers with expression data.
Validation PASSED (CDH23 98.3rd percentile, median known gene 83.3%).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

data/report/reproducibility.json

@@ -1,6 +1,6 @@
 {
-  "run_id": "093b405b-5a20-4f35-b5b8-04f02451789d",
-  "timestamp": "2026-02-15T21:49:14.940206+00:00",
+  "run_id": "f5587e39-163b-418c-8ac2-593b47323f34",
+  "timestamp": "2026-02-16T01:59:18.969516+00:00",
   "pipeline_version": "0.1.0",
   "parameters": {
     "gnomad": 0.2,
@@ -49,9 +49,9 @@
   ],
   "validation_metrics": {},
   "tier_statistics": {
-    "total": 21177,
-    "high": 82,
-    "medium": 9626,
-    "low": 11469
+    "total": 18243,
+    "high": 4,
+    "medium": 8051,
+    "low": 10188
   }
 }