refactor: remove redundant Decode(TPolyline) overload from AbstractPolylineDecoder

IPolylineDecoder already has cancellationToken = default, making the no-token
overload unnecessary. Callers can call Decode(polyline) directly via the interface.

Agent-Logs-Url: https://github.com/petesramek/polyline-algorithm-csharp/sessions/0ad5e8c4-b82b-4f8c-805d-29afa8c45722

Co-authored-by: petesramek <2333452+petesramek@users.noreply.github.com>

Author: Copilot

src/PolylineAlgorithm/Abstraction/AbstractPolylineDecoder.cs

@@ -54,27 +54,6 @@ protected AbstractPolylineDecoder(PolylineEncodingOptions options) {
         /// </summary>
         public PolylineEncodingOptions Options { get; }
 
-        /// <summary>
-        /// Decodes an encoded <typeparamref name="TPolyline"/> into a sequence of <typeparamref name="TCoordinate"/> instances.
-        /// </summary>
-        /// <param name="polyline">
-        /// The <typeparamref name="TPolyline"/> instance containing the encoded polyline string to decode.
-        /// </param>
-        /// <returns>
-        /// An <see cref="IEnumerable{T}"/> of <typeparamref name="TCoordinate"/> representing the decoded latitude and longitude pairs.
-        /// </returns>
-        /// <exception cref="ArgumentNullException">
-        /// Thrown when <paramref name="polyline"/> is <see langword="null"/>.
-        /// </exception>
-        /// <exception cref="ArgumentException">
-        /// Thrown when <paramref name="polyline"/> is empty.
-        /// </exception>
-        /// <exception cref="InvalidPolylineException">
-        /// Thrown when the polyline format is invalid or malformed at a specific position.
-        /// </exception>
-        public IEnumerable<TCoordinate> Decode(TPolyline polyline)
-            => Decode(polyline, CancellationToken.None);
-
         /// <summary>
         /// Decodes an encoded <typeparamref name="TPolyline"/> into a sequence of <typeparamref name="TCoordinate"/> instances,
         /// with support for cancellation.