fix: resolve JOIN explosion from duplicate gene_ids across evidence tables

- scoring/integration.py: Use CTEs with GROUP BY gene_id to deduplicate
  all evidence tables before LEFT JOIN (gnomAD had 211K rows for 18K
  genes due to per-transcript data; annotation/localization also had dupes)
- literature/transform.py: Deduplicate gene_symbols before PubMed queries
  to avoid querying the same symbol multiple times
- evidence_cmd.py: Fix Polars .alias() error in literature summary display
- Updated report results with full 6-layer scoring (44 HIGH, 7268 MEDIUM)
- Validation PASSED: known Usher genes median percentile 86.9%

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

data/report/candidates.provenance.yaml

@@ -1,12 +1,12 @@
-generated_at: '2026-02-12T18:42:59.932245+00:00'
+generated_at: '2026-02-15T20:47:53.707513+00:00'
 output_files:
 - candidates.tsv
 - candidates.parquet
 statistics:
-  total_candidates: 18116
-  high_count: 0
-  medium_count: 2151
-  low_count: 15965
+  total_candidates: 19342
+  high_count: 44
+  medium_count: 7268
+  low_count: 12030
 column_count: 22
 column_names:
 - gene_id