Refine Rule 3: TRIVIAL, 0ms elapsed, severity demotion

Dashboard/Services/PlanAnalyzer.cs

@@ -38,9 +38,12 @@
     private static void AnalyzeStatement(PlanStatement stmt)
     {
         // Rule 3: Serial plan with reason
-        // Skip trivial statements (e.g., variable assignments, constant scans) — not worth warning about
+        // Skip: trivial cost (< 0.01), TRIVIAL optimization (can't go parallel anyway),
+        // and 0ms actual elapsed time (not worth flagging).
         if (!string.IsNullOrEmpty(stmt.NonParallelPlanReason)
-            && stmt.StatementSubTreeCost >= 0.01)
+            && stmt.StatementSubTreeCost >= 0.01
+            && stmt.StatementOptmLevel != "TRIVIAL"
+            && !(stmt.QueryTimeStats != null && stmt.QueryTimeStats.ElapsedTimeMs == 0))
         {
             var reason = stmt.NonParallelPlanReason switch
             {
@@ -52,11 +55,13 @@
                 _ => stmt.NonParallelPlanReason
             };
 
+            var isExplicit = stmt.NonParallelPlanReason is "MaxDOPSetToOne" or "QueryHintNoParallelSet";
+
             stmt.PlanWarnings.Add(new PlanWarning
             {
                 WarningType = "Serial Plan",
                 Message = $"Query running serially: {reason}.",
-                Severity = PlanWarningSeverity.Warning
+                Severity = isExplicit ? PlanWarningSeverity.Warning : PlanWarningSeverity.Info
             });
         }
 
@@ -870,7 +875,7 @@
         // Rule 28: Row Count Spool — NOT IN with nullable column
         // Pattern: Row Count Spool with high rewinds, child scan has IS NULL predicate,
         // and statement text contains NOT IN
         if (node.PhysicalOp.Contains("Row Count Spool"))
         {
             var rewinds = node.HasActualStats ? (double)node.ActualRewinds : node.EstimateRewinds;
             if (rewinds > 10000 && HasNotInPattern(node, stmt))

Lite/Services/PlanAnalyzer.cs

@@ -38,9 +38,12 @@
     private static void AnalyzeStatement(PlanStatement stmt)
     {
         // Rule 3: Serial plan with reason
-        // Skip trivial statements (e.g., variable assignments, constant scans) — not worth warning about
+        // Skip: trivial cost (< 0.01), TRIVIAL optimization (can't go parallel anyway),
+        // and 0ms actual elapsed time (not worth flagging).
         if (!string.IsNullOrEmpty(stmt.NonParallelPlanReason)
-            && stmt.StatementSubTreeCost >= 0.01)
+            && stmt.StatementSubTreeCost >= 0.01
+            && stmt.StatementOptmLevel != "TRIVIAL"
+            && !(stmt.QueryTimeStats != null && stmt.QueryTimeStats.ElapsedTimeMs == 0))
         {
             var reason = stmt.NonParallelPlanReason switch
             {
@@ -52,11 +55,13 @@
                 _ => stmt.NonParallelPlanReason
             };
 
+            var isExplicit = stmt.NonParallelPlanReason is "MaxDOPSetToOne" or "QueryHintNoParallelSet";
+
             stmt.PlanWarnings.Add(new PlanWarning
             {
                 WarningType = "Serial Plan",
                 Message = $"Query running serially: {reason}.",
-                Severity = PlanWarningSeverity.Warning
+                Severity = isExplicit ? PlanWarningSeverity.Warning : PlanWarningSeverity.Info
             });
         }
 
@@ -869,7 +874,7 @@
         // Rule 28: Row Count Spool — NOT IN with nullable column
         // Pattern: Row Count Spool with high rewinds, child scan has IS NULL predicate,
         // and statement text contains NOT IN
         if (node.PhysicalOp.Contains("Row Count Spool"))
         {
             var rewinds = node.HasActualStats ? (double)node.ActualRewinds : node.EstimateRewinds;
             if (rewinds > 10000 && HasNotInPattern(node, stmt))