Add TBar, TBarSeries, TSeries, TValue, and IFeed implementations with comprehensive documentation and examples

- Introduced TBar struct for efficient OHLCV data representation.
- Implemented TBarSeries class for high-performance collection of TBar instances using Structure of Arrays (SoA) layout.
- Added TSeries class for time-series data management with zero-copy access.
- Created TValue struct for time-value pairs with implicit conversions.
- Defined IFeed interface for consistent data feed implementations.
- Developed CsvFeed class for loading historical OHLCV data from CSV files.
- Implemented GBM class for generating synthetic financial data using Geometric Brownian Motion.
- Added Quantower project files for Averages indicator with necessary dependencies and configurations.
- Included extensive usage examples and notebooks for TBar, TBarSeries, TSeries, TValue, and feed implementations.

lib/core/tvalue/TValue.Notebook.dib

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+#!meta
+
+{"kernelInfo":{"defaultKernelName":"csharp","items":[{"name":"csharp"},{"name":"fsharp","languageName":"F#","aliases":["f#","fs"]},{"name":"html","languageName":"HTML"},{"name":"http","languageName":"HTTP"},{"name":"javascript","languageName":"JavaScript","aliases":["js"]},{"name":"mermaid","languageName":"Mermaid"},{"name":"pwsh","languageName":"PowerShell","aliases":["powershell"]},{"name":"value"}]}}
+
+#!markdown
+
+# TValue Examples
+
+This notebook demonstrates the usage of `TValue`, the fundamental data structure in QuanTAlib.
+
+For detailed documentation, see [TValue.md](TValue.md).
+
+#!csharp
+
+// Reference the library
+#r "..\..\bin\QuanTAlib.dll"
+
+using System;
+using QuanTAlib;
+
+#!markdown
+
+## Creating TValue
+
+You can create a `TValue` using `DateTime` or `ticks`.
+
+#!csharp
+
+// Using DateTime
+var now = DateTime.UtcNow;
+var val1 = new TValue(now, 100.5);
+Console.WriteLine($"Created TValue: Time={val1.AsDateTime}, Value={val1.Value}");
+
+// Using Ticks
+long ticks = now.AddMinutes(1).Ticks;
+var val2 = new TValue(ticks, 101.0);
+Console.WriteLine($"Created TValue: Time={val2.AsDateTime}, Value={val2.Value}");
+
+#!markdown
+
+## Implicit Conversions
+
+`TValue` supports implicit conversions to `double` and `DateTime` for convenience.
+
+#!csharp
+
+double d = val1; // Implicitly gets Value
+DateTime t = val1; // Implicitly gets Time (as DateTime)
+
+Console.WriteLine($"Double: {d}");
+Console.WriteLine($"DateTime: {t}");
+
+// Arithmetic operations using implicit conversion
+double result = val1 + 5.0;
+Console.WriteLine($"Result (100.5 + 5.0): {result}");
+
+#!markdown
+
+## Immutability
+
+`TValue` is immutable. You cannot change its properties after creation.
+
+#!csharp
+
+// val1.Value = 200; // Error: Property or indexer 'TValue.Value' cannot be assigned to -- it is read only
+
+// To "change" a value, create a new instance
+var val3 = new TValue(val1.Time, 200.0);
+Console.WriteLine($"New TValue: {val3.Value}");

lib/core/tvalue/TValue.md

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+# TValue: Time-Value Pair
+
+## Overview
+
+`TValue` is the fundamental building block of QuanTAlib. It represents a single data point in a time series, consisting of a timestamp and a double-precision floating-point value.
+
+It is implemented as a lightweight `readonly struct` to ensure immutability and high performance (stack allocation, no GC overhead).
+
+## Structure
+
+```csharp
+public readonly struct TValue
+{
+    public readonly long Time;   // Ticks (UTC)
+    public readonly double Value; // Data value
+    public readonly bool IsNew;   // Metadata for streaming (optional usage)
+}
+```
+
+## Key Features
+
+*   **Lightweight**: 24 bytes (long + double + bool + padding).
+*   **Immutable**: Thread-safe by design.
+*   **Implicit Conversions**: Can be implicitly converted to `double` (returns Value) and `DateTime` (returns Time).
+*   **Performance**: Designed for high-frequency trading and large dataset processing.
+
+## Usage
+
+`TValue` is used throughout the library for:
+*   Input to indicators (`Update(TValue)`).
+*   Output from indicators (`Value` property).
+*   Elements in `TSeries`.
+
+## Constructors
+
+*   `new TValue(long time, double value, bool isNew = true)`
+*   `new TValue(DateTime time, double value, bool isNew = true)`