Add read timeout control to SshSession and error handling for channel timeouts

Introduce `SetReadTimeout` and `DisableReadTimeout` methods to manage channel read timeouts explicitly. Enhance `SshChannelStream` to throw `SshException` for read timeout errors.

Author: 0x25CBFC4F

src/NullOpsDevs.LibSsh/Core/SshChannelStream.cs

@@ -1,3 +1,4 @@
+using NullOpsDevs.LibSsh.Exceptions;
 using NullOpsDevs.LibSsh.Generated;
 
 namespace NullOpsDevs.LibSsh.Core;
@@ -85,8 +86,15 @@ private int ReadCore(Span<byte> buffer)
 
             if (bytesRead < 0)
             {
-                // Error occurred - treat as EOF for stream purposes
-                // The actual error can be retrieved via the session
+                // Check for read timeout explicitly
+                if (bytesRead == LibSshNative.LIBSSH2_ERROR_TIMEOUT)
+                {
+                    throw new SshException(
+                        "SSH channel read timed out. Consider calling DisableReadTimeout() or increasing the timeout with SetReadTimeout().",
+                        SshError.Timeout);
+                }
+
+                // Other errors - treat as EOF for stream purposes
                 _isEof = true;
                 return 0;
             }

src/NullOpsDevs.LibSsh/SshSession.cs

@@ -284,6 +284,24 @@ public unsafe void DisableSessionTimeout()
 
         libssh2_session_set_timeout(SessionPtr, 0);
     }
+    
+    /// <summary>
+    /// Disables the read timeout, allowing read operations to wait indefinitely for data.
+    /// </summary>
+    /// <remarks>
+    /// <para>By default, libssh2 has no read timeout. Use this method to explicitly disable any previously set read timeout.</para>
+    /// <para>The read timeout controls how long channel read operations (like reading command output) will wait for data before returning LIBSSH2_ERROR_TIMEOUT (-9).</para>
+    /// <para>The session must be in <see cref="SshConnectionStatus.Connected"/> or <see cref="SshConnectionStatus.LoggedIn"/> status before calling this method.</para>
+    /// </remarks>
+    /// <seealso cref="SetReadTimeout"/>
+    /// <seealso cref="DisableSessionTimeout"/>
+    public unsafe void DisableReadTimeout()
+    {
+        EnsureInitialized();
+        EnsureInStatuses(SshConnectionStatus.Connected, SshConnectionStatus.LoggedIn);
+
+        libssh2_session_set_read_timeout(SessionPtr, 0);
+    }
 
     /// <summary>
     /// Sets the maximum time to wait for SSH operations to complete.
@@ -307,6 +325,33 @@ public unsafe void SetSessionTimeout(TimeSpan timeout)
 
         libssh2_session_set_timeout(SessionPtr, (int) timeout.TotalMilliseconds);
     }
+    
+    /// <summary>
+    /// Sets the maximum time to wait for data when reading from SSH channels.
+    /// </summary>
+    /// <param name="timeout">The timeout duration. Must be greater than zero and less than <see cref="int.MaxValue"/> milliseconds.</param>
+    /// <exception cref="ArgumentOutOfRangeException">Thrown if the timeout is negative or exceeds the maximum allowed value.</exception>
+    /// <remarks>
+    /// <para>This timeout applies specifically to channel read operations (e.g., reading command output via streaming).</para>
+    /// <para>If no data is received within the specified time, the read operation will return LIBSSH2_ERROR_TIMEOUT (-9).</para>
+    /// <para>This is separate from <see cref="SetSessionTimeout"/> which controls the overall session timeout.</para>
+    /// <para>The session must be in <see cref="SshConnectionStatus.Connected"/> or <see cref="SshConnectionStatus.LoggedIn"/> status before calling this method.</para>
+    /// </remarks>
+    /// <seealso cref="DisableReadTimeout"/>
+    /// <seealso cref="SetSessionTimeout"/>
+    public unsafe void SetReadTimeout(TimeSpan timeout)
+    {
+        if (timeout < TimeSpan.Zero)
+            throw new ArgumentOutOfRangeException(nameof(timeout), timeout, "Timeout must be greater than zero");
+
+        if (timeout.TotalMilliseconds > int.MaxValue)
+            throw new ArgumentOutOfRangeException(nameof(timeout), timeout, "Timeout cannot be greater than int.MaxValue milliseconds");
+
+        EnsureInitialized();
+        EnsureInStatuses(SshConnectionStatus.Connected, SshConnectionStatus.LoggedIn);
+
+        libssh2_session_set_read_timeout(SessionPtr, (int)timeout.TotalMilliseconds);
+    }
 
     /// <summary>
     /// Sends a keepalive message to the remote SSH server.