Add Savitzky-Golay Moving Average (SGMA) Indicator Implementation

- Implemented SgmaIndicator class in C# with properties for Period, Degree, and Source.
- Added unit tests for SgmaIndicator covering constructor defaults, initialization, and various update scenarios.
- Created a new Quantower adapter for the SGMA indicator, including input parameters and line series setup.
- Removed legacy SGMA implementation and tests to streamline the codebase.
- Updated project files to include new indicator and tests in the build process.
- Generated a missing indicators report and outlined a plan for oscillator documentation rewrite.

lib/trends_FIR/sgma/Sgma.Quantower.cs

@@ -0,0 +1,58 @@
+using System.Runtime.CompilerServices;
+using TradingPlatform.BusinessLayer;
+
+namespace QuanTAlib;
+
+[SkipLocalsInit]
+public sealed class SgmaIndicator : Indicator, IWatchlistIndicator
+{
+    [InputParameter("Period", sortIndex: 1, 3, 2000, 1, 0)]
+    public int Period { get; set; } = 9;
+
+    [InputParameter("Degree", sortIndex: 2, 0, 4, 1, 0)]
+    public int Degree { get; set; } = 2;
+
+    [IndicatorExtensions.DataSourceInput]
+    public SourceType Source { get; set; } = SourceType.Close;
+
+    [InputParameter("Show cold values", sortIndex: 21)]
+    public bool ShowColdValues { get; set; } = true;
+
+    private Sgma _sgma = null!;
+    private readonly LineSeries _series;
+    private string _sourceName = null!;
+    private Func<IHistoryItem, double> _priceSelector = null!;
+
+    public static int MinHistoryDepths => 0;
+    int IWatchlistIndicator.MinHistoryDepths => MinHistoryDepths;
+
+    public override string ShortName => $"SGMA {Period},{Degree}:{_sourceName}";
+    public override string SourceCodeLink => "https://github.com/mihakralj/QuanTAlib/blob/main/lib/trends_FIR/sgma/Sgma.cs";
+
+    public SgmaIndicator()
+    {
+        OnBackGround = true;
+        SeparateWindow = false;
+        Name = "SGMA - Savitzky-Golay Moving Average";
+        Description = "Polynomial-fitting FIR filter preserving peaks and inflection points";
+        _series = new LineSeries(name: $"SGMA {Period}", color: IndicatorExtensions.Averages, width: 2, style: LineStyle.Solid);
+        AddLineSeries(_series);
+    }
+
+    protected override void OnInit()
+    {
+        _priceSelector = Source.GetPriceSelector();
+        _sourceName = Source.ToString();
+        _sgma = new Sgma(Period, Degree);
+        base.OnInit();
+    }
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    protected override void OnUpdate(UpdateArgs args)
+    {
+        bool isNew = args.IsNewBar();
+        var item = HistoricalData[Count - 1, SeekOriginHistory.Begin];
+        double value = _sgma.Update(new TValue(item.TimeLeft.Ticks, _priceSelector(item)), isNew).Value;
+        _series.SetValue(value, _sgma.IsHot, ShowColdValues);
+    }
+}