SIMD Refactor: Merge simd-dev into dev (#55)

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
Co-authored-by: aider (openrouter/anthropic/claude-sonnet-4) <aider@aider.chat>
Co-authored-by: Warp <agent@warp.dev>

lib/feeds/IFeed.cs

@@ -0,0 +1,35 @@
+namespace QuanTAlib;
+
+/// <summary>
+/// Interface for data feeds that provide TBar (OHLCV) data.
+/// Implementations include synthetic generators (GBM), API-based feeds (AlphaVantage),
+/// file readers (CSV), and real-time streams (WebSocket).
+/// </summary>
+public interface IFeed
+{
+    /// <summary>
+    /// Gets the next bar from the feed with full bidirectional control.
+    /// </summary>
+    /// <param name="isNew">
+    /// Input: Request for new bar (true) or update current bar (false).
+    /// Output: Actual behavior - may differ if feed cannot honor request (e.g., end of data).
+    /// </param>
+    /// <returns>The bar (new or updated)</returns>
+    TBar Next(ref bool isNew);
+
+    /// <summary>
+    /// Gets the next bar from the feed with simple control.
+    /// </summary>
+    /// <param name="isNew">Request for new bar (true) or update current bar (false). Defaults to true.</param>
+    /// <returns>The bar (new or updated)</returns>
+    TBar Next(bool isNew = true);
+
+    /// <summary>
+    /// Gets multiple bars in batch with explicit time parameters.
+    /// </summary>
+    /// <param name="count">Number of bars to retrieve</param>
+    /// <param name="startTime">Starting timestamp for first bar (in ticks)</param>
+    /// <param name="interval">Time interval between bars</param>
+    /// <returns>Series containing the requested bars</returns>
+    TBarSeries Fetch(int count, long startTime, TimeSpan interval);
+}