fix(calcite): return exact Long sum, not a promoted Double (S2154)

The ?: ternary 'isFloating ? Double.valueOf(d) : Long.valueOf(l)' undergoes
binary numeric promotion — it unboxes both arms and widens the Long to double,
so an integer-column SUM was silently returned as a Double, defeating the exact
long accumulation. Return via if/else (reference, no promotion).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: dfa1

calcite/src/main/java/io/github/dfa1/vortex/calcite/VortexAggregates.java

@@ -120,6 +120,11 @@ private static Number scanSum(VortexReader reader, String column) {
                 }
             }
         }
-        return isFloating ? Double.valueOf(doubleSum) : Long.valueOf(longSum);
+        // Return via if/else, not a ?: ternary: a numeric conditional unboxes both branches and
+        // widens the Long to double, silently turning an integer-column sum into a Double.
+        if (isFloating) {
+            return doubleSum;
+        }
+        return longSum;
     }
 }