Initialize CBDD solution and add a .NET-focused gitignore for generated artifacts.

src/CBDD.Core/Indexing/VectorSearchExtensions.cs

@@ -0,0 +1,30 @@
+namespace ZB.MOM.WW.CBDD.Core.Indexing;
+
+public static class VectorSearchExtensions
+{
+    /// <summary>
+    /// Performs a similarity search on a vector property.
+    /// This method is a marker for the LINQ query provider and is optimized using HNSW indexes if available.
+    /// </summary>
+    /// <param name="vector">The vector property of the entity.</param>
+    /// <param name="query">The query vector to compare against.</param>
+    /// <param name="k">Number of nearest neighbors to return.</param>
+    /// <returns>True if the document is part of the top-k results (always returns true when evaluated in memory for compilation purposes).</returns>
+    public static bool VectorSearch(this float[] vector, float[] query, int k)
+    {
+        return true;
+    }
+
+    /// <summary>
+    /// Performs a similarity search on a collection of vector properties.
+    /// Used for entities with multiple vectors per document.
+    /// </summary>
+    /// <param name="vectors">The vector collection of the entity.</param>
+    /// <param name="query">The query vector to compare against.</param>
+    /// <param name="k">Number of nearest neighbors to return.</param>
+    /// <returns>True if the document is part of the top-k results (always returns true when evaluated in memory for compilation purposes).</returns>
+    public static bool VectorSearch(this IEnumerable<float[]> vectors, float[] query, int k)
+    {
+        return true;
+    }
+}