fix(metrics): exclude excluded_from_metrics trades from trades_dominated_by_mfld counter

The trades_dominated_by_mfld counter omitted the excluded_from_metrics
filter, so the admin-closed Maine governor trade inflated it to 1 while
attribution/features (which exclude such trades) were empty.

Add excluded_from_metrics IS NOT TRUE and mfld_match_status = 'accepted'
to the query so the counter is consistent with the attribution and
feature-metrics endpoints.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

api/main.py

@@ -223,7 +223,9 @@ async def get_manifold_matches():
     summary.all_time — accepted/rejected/no_results across every matcher version.
     summary.legacy.accepted_without_outcome_type — pre-outcome-guard accepted
       records that the current matcher would reject (not counted in current_version).
-    summary.trades_dominated_by_mfld — open trades where feat_mfld_lo is the largest signal.
+    summary.trades_dominated_by_mfld — non-excluded accepted-match trades where
+      feat_mfld_lo is the largest signal (consistent with attribution/features,
+      which also exclude excluded_from_metrics trades).
 
     recent_matches: last 50 rows from manifold_match_audit, newest first, each
       tagged with matcher_version.