[tcp] add OPENTHREAD_CONFIG_TCP_ENABLE guards to headers (#13195)

This commit wraps the contents of `tcp6.hpp` and `tcp6_ext.hpp` with
`#if OPENTHREAD_CONFIG_TCP_ENABLE` feature guards to ensure that TCP
definitions and types are cleanly excluded when TCP support is disabled
in the build configuration. Additionally, it explicitly disables the
`OPENTHREAD_CONFIG_TCP_ENABLE` feature flag in the Toranj test
configuration to validate building without TCP support.

src/core/net/tcp6.hpp

@@ -36,6 +36,8 @@
 
 #include "openthread-core-config.h"
 
+#if OPENTHREAD_CONFIG_TCP_ENABLE
+
 #include <openthread/tcp.h>
 
 #include "common/as_core_type.hpp"
@@ -592,4 +594,6 @@ DefineCoreType(otTcpListener, Ip6::Tcp::Listener);
 
 } // namespace ot
 
+#endif // OPENTHREAD_CONFIG_TCP_ENABLE
+
 #endif // OT_CORE_NET_TCP6_HPP_

src/core/net/tcp6_ext.hpp

@@ -36,6 +36,8 @@
 
 #include "openthread-core-config.h"
 
+#if OPENTHREAD_CONFIG_TCP_ENABLE
+
 #include <openthread/tcp_ext.h>
 
 #include "net/tcp6.hpp"
@@ -130,4 +132,6 @@ DefineCoreType(otTcpCircularSendBuffer, Ip6::TcpCircularSendBuffer);
 
 } // namespace ot
 
+#endif // OPENTHREAD_CONFIG_TCP_ENABLE
+
 #endif // OT_CORE_NET_TCP6_EXT_HPP_

tests/toranj/openthread-core-toranj-config.h

@@ -141,6 +141,8 @@
 
 #define OPENTHREAD_CONFIG_IP6_SLAAC_DEPRECATION_INTERVAL 30
 
+#define OPENTHREAD_CONFIG_TCP_ENABLE 0
+
 #define OPENTHREAD_CONFIG_MAC_FILTER_ENABLE 1
 
 #define OPENTHREAD_CONFIG_MAC_FILTER_SIZE 80