feat(subscriptions): update event subscription handling to use non-nullable source parameters; remove defensive null checks

.clinerules/AGENTS.md

@@ -81,6 +81,7 @@ Directory: `lib/[category]/[name]/` (e.g., `lib/trends/sma/`)
 * Validate all parameters (throw `ArgumentException` for invalid values).
 * Initialize `Name` property (e.g., `$"Sma({period})"`);
 * Support chaining: `public [Name](ITValuePublisher source, ...)`
+* **Event Subscription:** Subscribe to events directly (`source.Pub += ...`) when the source is passed as a non-nullable parameter. Do not use defensive null checks (`if (_source != null)`).
 
 ### The `Update` Method Contract
 

lib/core/simd/SimdExtensions.cs

@@ -551,7 +551,7 @@ public static class SimdExtensions
         vSum3 = Avx512F.Add(vSum3, vSum4);
         vSum = Avx512F.Add(vSum, vSum3);
 
-        Vector256<double> v256 = Avx512F.Add(vSum.GetLower(), vSum.GetUpper());
+        Vector256<double> v256 = Avx.Add(vSum.GetLower(), vSum.GetUpper());
         Vector128<double> lower = v256.GetLower();
         Vector128<double> upper = v256.GetUpper();
         Vector128<double> combined = Sse2.Add(lower, upper);

lib/trends/bessel/Bessel.cs

@@ -69,7 +69,7 @@ public sealed class Bessel : AbstractBase, IDisposable
     {
         _publisher = source;
         _handler = item => Update(item);
-        _publisher.Pub += _handler;
+        source.Pub += _handler;
     }
 
     /// <summary>
@@ -85,7 +85,7 @@ public sealed class Bessel : AbstractBase, IDisposable
 
         _publisher = source;
         _handler = item => Update(item);
-        _publisher.Pub += _handler;
+        source.Pub += _handler;
     }
 
     public override bool IsHot => _state.IsHot;

lib/trends/blma/Blma.Tests.cs

@@ -25,8 +25,7 @@ public class BlmaTests
     [Fact]
     public void Constructor_ValidatesSource()
     {
-        Assert.Throws<ArgumentNullException>(() => new Blma(null!, 10));
-        Assert.Throws<ArgumentException>(() => new Blma(new object(), 10));
+        Assert.Throws<NullReferenceException>(() => new Blma(null!, 10));
     }
 
     [Fact]

lib/trends/blma/Blma.cs

@@ -33,19 +33,10 @@ public sealed class Blma : AbstractBase, IDisposable
         _weightSum = CalculateWeights(period, _weights);
     }
 
-    public Blma(object source, int period) : this(period)
+    public Blma(ITValuePublisher source, int period) : this(period)
     {
-        ArgumentNullException.ThrowIfNull(source);
-
-        if (source is ITValuePublisher pub)
-        {
-            _publisher = pub;
-            _publisher.Pub += Handle;
-        }
-        else
-        {
-            throw new ArgumentException("Source must implement ITValuePublisher", nameof(source));
-        }
+        _publisher = source;
+        source.Pub += Handle;
     }
 
     public void Dispose()

lib/trends/dema/Dema.cs

@@ -58,7 +58,7 @@ public sealed class Dema : AbstractBase, IDisposable
     {
         _publisher = source;
         _listener = (item) => Update(item);
-        _publisher.Pub += _listener;
+        source.Pub += _listener;
     }
 
     public Dema(double alpha)

lib/trends/pwma/Pwma.Tests.cs

@@ -8,7 +8,7 @@ public class PwmaTests
     {
         Assert.Throws<ArgumentException>(() => new Pwma(0));
         Assert.Throws<ArgumentException>(() => new Pwma(-1));
-        Assert.Throws<ArgumentNullException>(() => new Pwma(null!, 10));
+        Assert.Throws<NullReferenceException>(() => new Pwma(null!, 10));
 
         var pwma = new Pwma(10);
         Assert.NotNull(pwma);

lib/trends/pwma/Pwma.cs

@@ -56,7 +56,6 @@ public sealed class Pwma : AbstractBase
 
     public Pwma(ITValuePublisher source, int period) : this(period)
     {
-        if (source == null) throw new ArgumentNullException(nameof(source));
         source.Pub += (item) => Update(item);
     }
 

lib/trends/t3/T3.cs

@@ -81,7 +81,7 @@ public sealed class T3 : AbstractBase, IDisposable
     {
         _publisher = source;
         _handler = (item) => Update(item);
-        _publisher.Pub += _handler;
+        source.Pub += _handler;
     }
 
     /// <summary>

lib/trends/trima/Trima.cs

@@ -52,7 +52,7 @@ public sealed class Trima : AbstractBase, IDisposable
     public Trima(ITValuePublisher source, int period) : this(period)
     {
         _publisher = source;
-        _publisher.Pub += _updateHandler;
+        source.Pub += _updateHandler;
     }
 
     public void Dispose()

lib/trends/vidya/Vidya.cs

@@ -60,7 +60,7 @@ public sealed class Vidya : AbstractBase, IDisposable
     {
         _source = source;
         _pubHandler = (item) => Update(item);
-        _source.Pub += _pubHandler;
+        source.Pub += _pubHandler;
     }
 
     public void Dispose()

lib/trends/wma/Wma.cs

@@ -69,7 +69,7 @@ public sealed class Wma : AbstractBase, IDisposable
     {
         _source = source;
         _handler = (item) => Update(item);
-        _source.Pub += _handler;
+        source.Pub += _handler;
     }
 
     public void Dispose()