docs: remove C# Implementation Considerations sections, clean up temp scripts, reorganize test files

- Remove 'C# Implementation Considerations' sections from 34 indicator .md files
- Delete 29 temp PowerShell scripts (_fix_mojibake.ps1, _hex_scan.ps1, etc.)
- Move test files into tests/ subdirectories for consistent project structure
- Add trader-focused bullet points to indicator documentation

lib/errors/mae/tests/Mae.Tests.cs

@@ -0,0 +1,366 @@
+namespace QuanTAlib.Tests;
+
+public class MaeTests
+{
+    [Fact]
+    public void Constructor_ValidatesInput()
+    {
+        Assert.Throws<ArgumentException>(() => new Mae(0));
+        Assert.Throws<ArgumentException>(() => new Mae(-1));
+
+        var mae = new Mae(10);
+        Assert.NotNull(mae);
+    }
+
+    [Fact]
+    public void Properties_Accessible()
+    {
+        var mae = new Mae(10);
+
+        Assert.Equal(0, mae.Last.Value);
+        Assert.False(mae.IsHot);
+        Assert.Contains("Mae", mae.Name, StringComparison.Ordinal);
+
+        mae.Update(100, 105);
+        Assert.NotEqual(0, mae.Last.Value);
+    }
+
+    [Fact]
+    public void IsHot_BecomesTrueWhenBufferFull()
+    {
+        const int period = 5;
+        var mae = new Mae(period);
+
+        for (int i = 0; i < period - 1; i++)
+        {
+            Assert.False(mae.IsHot, $"IsHot should be false at index {i}");
+            mae.Update(i * 10, i * 10 + 5);
+        }
+
+        mae.Update((period - 1) * 10, (period - 1) * 10 + 5);
+        Assert.True(mae.IsHot, "IsHot should be true after period updates");
+    }
+
+    [Fact]
+    public void Mae_CalculatesCorrectly()
+    {
+        var mae = new Mae(3);
+
+        // |10 - 15| = 5
+        var res1 = mae.Update(10, 15);
+        Assert.Equal(5.0, res1.Value, 10);
+
+        // |20 - 30| = 10, Mean = (5 + 10) / 2 = 7.5
+        var res2 = mae.Update(20, 30);
+        Assert.Equal(7.5, res2.Value, 10);
+
+        // |30 - 25| = 5, Mean = (5 + 10 + 5) / 3 = 6.666...
+        var res3 = mae.Update(30, 25);
+        Assert.Equal(20.0 / 3.0, res3.Value, 10);
+
+        // |40 - 35| = 5, Window slides: (10 + 5 + 5) / 3 = 6.666...
+        var res4 = mae.Update(40, 35);
+        Assert.Equal(20.0 / 3.0, res4.Value, 10);
+    }
+
+    [Fact]
+    public void Mae_PerfectPrediction_ReturnsZero()
+    {
+        var mae = new Mae(5);
+
+        for (int i = 0; i < 10; i++)
+        {
+            mae.Update(i * 10, i * 10); // Perfect prediction
+        }
+
+        Assert.Equal(0.0, mae.Last.Value, 10);
+    }
+
+    [Fact]
+    public void Mae_ConstantError_ReturnsConstant()
+    {
+        var mae = new Mae(5);
+
+        for (int i = 0; i < 10; i++)
+        {
+            mae.Update(100, 110); // Constant error of 10
+        }
+
+        Assert.Equal(10.0, mae.Last.Value, 10);
+    }
+
+    [Fact]
+    public void Mae_NegativeError_TakesAbsoluteValue()
+    {
+        var mae = new Mae(3);
+
+        // Error = |15 - 10| = 5 (predicted > actual)
+        mae.Update(10, 15);
+        // Error = |20 - 30| = 10 (predicted > actual)
+        mae.Update(20, 30);
+        // Error = |50 - 25| = 25 (predicted < actual)
+        mae.Update(50, 25);
+
+        // Mean = (5 + 10 + 25) / 3 = 40 / 3
+        Assert.Equal(40.0 / 3.0, mae.Last.Value, 10);
+    }
+
+    [Fact]
+    public void Calc_IsNew_AcceptsParameter()
+    {
+        var mae = new Mae(10);
+
+        mae.Update(100, 110, isNew: true);
+        double value1 = mae.Last.Value;
+
+        mae.Update(100, 120, isNew: true);
+        double value2 = mae.Last.Value;
+
+        Assert.NotEqual(value1, value2);
+    }
+
+    [Fact]
+    public void Calc_IsNew_False_UpdatesValue()
+    {
+        var mae = new Mae(10);
+
+        mae.Update(100, 110);
+        mae.Update(100, 120, isNew: true);
+        double beforeUpdate = mae.Last.Value;
+
+        mae.Update(100, 130, isNew: false);
+        double afterUpdate = mae.Last.Value;
+
+        Assert.NotEqual(beforeUpdate, afterUpdate);
+    }
+
+    [Fact]
+    public void IterativeCorrections_RestoreToOriginalState()
+    {
+        var mae = new Mae(5);
+
+        double tenthActual = 0;
+        double tenthPredicted = 0;
+
+        // Feed 10 updates
+        for (int i = 0; i < 10; i++)
+        {
+            tenthActual = i * 10;
+            tenthPredicted = i * 10 + 5;
+            mae.Update(tenthActual, tenthPredicted);
+        }
+
+        double stateAfterTen = mae.Last.Value;
+
+        // Apply 5 corrections with isNew=false
+        for (int i = 0; i < 5; i++)
+        {
+            mae.Update(100 + i, 200 + i, isNew: false);
+        }
+
+        // Restore to original values
+        mae.Update(tenthActual, tenthPredicted, isNew: false);
+
+        Assert.Equal(stateAfterTen, mae.Last.Value, 10);
+    }
+
+    [Fact]
+    public void Reset_ClearsState()
+    {
+        var mae = new Mae(5);
+
+        for (int i = 0; i < 10; i++)
+        {
+            mae.Update(i * 10, i * 10 + 5);
+        }
+
+        Assert.True(mae.IsHot);
+
+        mae.Reset();
+
+        Assert.False(mae.IsHot);
+        Assert.Equal(0, mae.Last.Value);
+    }
+
+    [Fact]
+    public void NaN_Input_UsesLastValidValue()
+    {
+        var mae = new Mae(5);
+
+        mae.Update(100, 110);
+        mae.Update(110, 120);
+        mae.Update(120, 130);
+
+        var result = mae.Update(double.NaN, double.NaN);
+
+        Assert.True(double.IsFinite(result.Value));
+    }
+
+    [Fact]
+    public void Infinity_Input_UsesLastValidValue()
+    {
+        var mae = new Mae(5);
+
+        mae.Update(100, 110);
+        mae.Update(110, 120);
+
+        var result = mae.Update(double.PositiveInfinity, double.NegativeInfinity);
+
+        Assert.True(double.IsFinite(result.Value));
+    }
+
+    [Fact]
+    public void MultipleNaN_ContinuesWithLastValid()
+    {
+        var mae = new Mae(5);
+
+        mae.Update(100, 110);
+        mae.Update(110, 120);
+        mae.Update(120, 130);
+
+        var r1 = mae.Update(double.NaN, double.NaN);
+        var r2 = mae.Update(double.NaN, double.NaN);
+        var r3 = mae.Update(double.NaN, double.NaN);
+
+        Assert.True(double.IsFinite(r1.Value));
+        Assert.True(double.IsFinite(r2.Value));
+        Assert.True(double.IsFinite(r3.Value));
+    }
+
+    [Fact]
+    public void Mae_Throws_On_Single_Input()
+    {
+        var mae = new Mae(10);
+        Assert.Throws<NotSupportedException>(() => mae.Update(new TValue(DateTime.UtcNow, 1)));
+        Assert.Throws<NotSupportedException>(() => mae.Update(new TSeries()));
+        Assert.Throws<NotSupportedException>(() => mae.Prime([1, 2, 3]));
+    }
+
+    [Fact]
+    public void BatchSpan_MatchesStreaming()
+    {
+        int period = 5;
+        int count = 100;
+        var gbm = new GBM(startPrice: 100, mu: 0.05, sigma: 0.2, seed: 123);
+
+        double[] actual = new double[count];
+        double[] predicted = new double[count];
+        for (int i = 0; i < count; i++)
+        {
+            var bar = gbm.Next();
+            actual[i] = bar.Close;
+            predicted[i] = bar.Close * 1.05 + 2; // Offset prediction
+        }
+
+        // Streaming
+        var mae = new Mae(period);
+        var streamingResults = new double[count];
+        for (int i = 0; i < count; i++)
+        {
+            streamingResults[i] = mae.Update(actual[i], predicted[i]).Value;
+        }
+
+        // Batch
+        double[] batchResults = new double[count];
+        Mae.Batch(actual, predicted, batchResults, period);
+
+        // Compare
+        for (int i = 0; i < count; i++)
+        {
+            Assert.Equal(streamingResults[i], batchResults[i], 9);
+        }
+    }
+
+    [Fact]
+    public void BatchSpan_ValidatesInput()
+    {
+        double[] actual = [1, 2, 3, 4, 5];
+        double[] predicted = [1, 2, 3, 4, 5];
+        double[] output = new double[5];
+        double[] wrongSizeOutput = new double[3];
+        double[] wrongSizePredicted = new double[3];
+
+        // Period must be > 0
+        Assert.Throws<ArgumentException>(() =>
+            Mae.Batch(actual.AsSpan(), predicted.AsSpan(), output.AsSpan(), 0));
+        Assert.Throws<ArgumentException>(() =>
+            Mae.Batch(actual.AsSpan(), predicted.AsSpan(), output.AsSpan(), -1));
+
+        // Output must be same length as source
+        Assert.Throws<ArgumentException>(() =>
+            Mae.Batch(actual.AsSpan(), predicted.AsSpan(), wrongSizeOutput.AsSpan(), 3));
+
+        // Predicted must be same length as actual
+        Assert.Throws<ArgumentException>(() =>
+            Mae.Batch(actual.AsSpan(), wrongSizePredicted.AsSpan(), output.AsSpan(), 3));
+    }
+
+    [Fact]
+    public void Calculate_Works()
+    {
+        var actual = new TSeries();
+        var predicted = new TSeries();
+        var now = DateTime.UtcNow;
+
+        for (int i = 0; i < 10; i++)
+        {
+            actual.Add(now.AddMinutes(i), i * 10);
+            predicted.Add(now.AddMinutes(i), i * 10 + 5);
+        }
+
+        var results = Mae.Batch(actual, predicted, 3);
+
+        Assert.Equal(10, results.Count);
+        // All errors are 5, so MAE should be 5
+        Assert.Equal(5.0, results.Last.Value, 10);
+    }
+
+    [Fact]
+    public void Calculate_ValidatesMismatchedLengths()
+    {
+        var actual = new TSeries();
+        var predicted = new TSeries();
+
+        for (int i = 0; i < 10; i++)
+        {
+            actual.Add(DateTime.UtcNow, i);
+        }
+
+        for (int i = 0; i < 5; i++)
+        {
+            predicted.Add(DateTime.UtcNow, i);
+        }
+
+        Assert.Throws<ArgumentException>(() => Mae.Batch(actual, predicted, 3));
+    }
+
+    [Fact]
+    public void BatchSpan_HandlesNaN()
+    {
+        double[] actual = [100, 110, double.NaN, 130, 140];
+        double[] predicted = [105, 115, 125, double.NaN, 145];
+        double[] output = new double[5];
+
+        Mae.Batch(actual, predicted, output, 3);
+
+        foreach (var val in output)
+        {
+            Assert.True(double.IsFinite(val), $"Expected finite value but got {val}");
+        }
+    }
+
+    [Fact]
+    public void Mae_Resync_Works()
+    {
+        var mae = new Mae(5);
+
+        // Force many updates to trigger resync (ResyncInterval = 1000)
+        for (int i = 0; i < 1100; i++)
+        {
+            mae.Update(i, i + 10); // Constant error of 10
+        }
+
+        // After resync, result should still be correct
+        Assert.Equal(10.0, mae.Last.Value, 10);
+    }
+}

lib/errors/mae/tests/Mae.Validation.Tests.cs

@@ -0,0 +1,100 @@
+using MathNet.Numerics;
+using QuanTAlib.Tests;
+
+namespace QuanTAlib.Validation;
+
+public sealed class MaeValidationTests : IDisposable
+{
+    private readonly ValidationTestData _data = new();
+
+    public void Dispose() => _data.Dispose();
+
+    [Fact]
+    public void Mae_Matches_MathNet()
+    {
+        int[] periods = { 5, 10, 20, 50, 100 };
+
+        var quotes = _data.SkenderQuotes.ToList();
+        double[] actual = quotes.Select(q => (double)q.Close).ToArray();
+        double[] predicted = quotes.Select(q => (double)q.Open).ToArray();
+
+        foreach (int period in periods)
+        {
+            var mae = new Mae(period);
+
+            for (int i = 0; i < actual.Length; i++)
+            {
+                var val = mae.Update(
+                    new TValue(quotes[i].Date, actual[i]),
+                    new TValue(quotes[i].Date, predicted[i]));
+
+                // Validate last 100 bars
+                if (i >= actual.Length - 100 && i >= period - 1)
+                {
+                    var windowActual = actual[(i - period + 1)..(i + 1)];
+                    var windowPredicted = predicted[(i - period + 1)..(i + 1)];
+
+                    double expected = Distance.MAE(windowActual, windowPredicted);
+
+                    Assert.Equal(expected, val.Value, 1e-9);
+                }
+            }
+        }
+    }
+
+    [Fact]
+    public void Mae_Batch_Matches_MathNet()
+    {
+        int[] periods = { 5, 10, 20, 50, 100 };
+
+        var quotes = _data.SkenderQuotes.ToList();
+        double[] actual = quotes.Select(q => (double)q.Close).ToArray();
+        double[] predicted = quotes.Select(q => (double)q.Open).ToArray();
+
+        foreach (int period in periods)
+        {
+            double[] output = new double[actual.Length];
+            Mae.Batch(actual, predicted, output, period);
+
+            // Validate last 100 bars
+            for (int i = actual.Length - 100; i < actual.Length; i++)
+            {
+                if (i >= period - 1)
+                {
+                    var windowActual = actual[(i - period + 1)..(i + 1)];
+                    var windowPredicted = predicted[(i - period + 1)..(i + 1)];
+
+                    double expected = Distance.MAE(windowActual, windowPredicted);
+
+                    Assert.Equal(expected, output[i], 1e-9);
+                }
+            }
+        }
+    }
+
+    [Fact]
+    public void Mae_Correction_Recomputes()
+    {
+        var ind = new Mae(20);
+
+        // Build state well past warmup
+        for (int i = 0; i < 50; i++)
+        {
+            ind.Update(100.0 + (i * 0.5), 98.0 + (i * 0.5));
+        }
+
+        // Anchor bar
+        const double anchorActual = 125.0;
+        const double anchorPredicted = 123.0;
+        ind.Update(anchorActual, anchorPredicted, isNew: true);
+        double anchorResult = ind.Last.Value;
+
+        // Correction with dramatically different values — recompute must yield different result
+        ind.Update(anchorActual * 10, anchorPredicted * 10, isNew: false);
+        Assert.NotEqual(anchorResult, ind.Last.Value);
+
+        // Correction back to original — must exactly restore original result
+        ind.Update(anchorActual, anchorPredicted, isNew: false);
+        Assert.Equal(anchorResult, ind.Last.Value, 1e-9);
+    }
+}