chore(sonar): wrap independent assertions in Assert.Multiple (NUnit2045)

Driven by `dotnet format analyzers --diagnostics NUnit2045`. The fixer
groups consecutive independent `Assert.That(...)` calls into
`Assert.Multiple(() => { ... })`, so a failing assertion no longer
short-circuits the block — every failure inside the group is reported,
which gives much better diagnostics on multi-property tests.

Audit confirmed no Assert.Throws / Assert.Fail / Assert.Catch / Assert.Pass
/ Assert.DoesNotThrow got pulled inside a Multiple block (those need to
short-circuit). All 1180 tests pass.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

tests/Strata.SqlTools.PostgreSql.Tests/PostgreSql/QueryBreakdownCollectionTests.cs

@@ -182,9 +182,12 @@ public class QueryBreakdownCollectionTests
         // Act
         var result = _collection.ParseBatch(batchSql);
 
-        // Assert
-        Assert.That(result, Is.True);
-        Assert.That(_collection.Count, Is.GreaterThan(0));
+        Assert.Multiple(() =>
+        {
+            // Assert
+            Assert.That(result, Is.True);
+            Assert.That(_collection.Count, Is.GreaterThan(0));
+        });
     }
 
     [Test]
@@ -199,9 +202,12 @@ public class QueryBreakdownCollectionTests
         // Act
         var result = _collection.ParseBatch(batchSql);
 
-        // Assert
-        Assert.That(result, Is.True);
-        Assert.That(_collection.Count, Is.GreaterThan(0));
+        Assert.Multiple(() =>
+        {
+            // Assert
+            Assert.That(result, Is.True);
+            Assert.That(_collection.Count, Is.GreaterThan(0));
+        });
     }
 
     [Test]
@@ -284,8 +290,11 @@ public class QueryBreakdownCollectionTests
 
         // Assert
         Assert.That(sql, Does.Contain("SELECT"));
-        Assert.That(sql, Does.Contain(";"));
-        Assert.That(_collection, Has.Count.EqualTo(3));
+        Assert.Multiple(() =>
+        {
+            Assert.That(sql, Does.Contain(";"));
+            Assert.That(_collection, Has.Count.EqualTo(3));
+        });
     }
 
     #endregion