feat(tcp): TCPStreamer DataSources, in-process TCPStreamService, stream multiplexing and TCPStreamJoin

Add TCPStreamer/TCPStreamerClient (TCP transport behind the UDPSServerI/UDPSClientI
seam), an optional single in-process TCPStreamService serving many streams over
worker threads, multiplexed SUBSCRIBE (comma list, stream index in fragmentIdx),
and TCPStreamJoin, which merges several streams into one sample-and-hold stream
paced by a master. StreamHub takes a comma list of streams over one connection.
Includes GTests, E2E scenarios s58-s73 and docs.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Source/Components/Interfaces/TCPStreamService/TCPSStreamTapI.h

@@ -0,0 +1,40 @@
+#ifndef TCPS_STREAM_TAP_I_H_
+#define TCPS_STREAM_TAP_I_H_
+
+/**
+ * @file TCPSStreamTapI.h
+ * @brief Hooks used by TCPStreamJoin to follow the streams of a TCPStreamService.
+ *
+ * TCPSStreamTapI observes the CONFIG / DATA payloads a stream publishes (on the
+ * producer's thread, after the frame went to the subscribers). TCPSStreamObserverI
+ * observes streams registering with / leaving a service.
+ */
+
+#include "CompilerTypes.h"
+
+namespace MARTe {
+
+class TCPSServiceStream;
+
+class TCPSStreamTapI {
+public:
+    virtual ~TCPSStreamTapI() {}
+    /** A CONFIG payload was published (or the cached one is replayed on AddTap). */
+    virtual void OnTapConfig(TCPSServiceStream *source, const uint8 *payload, uint32 payloadSize) = 0;
+    /** A DATA payload was published. */
+    virtual void OnTapData(TCPSServiceStream *source, uint32 counter, const uint8 *payload,
+                           uint32 payloadSize) = 0;
+};
+
+class TCPSStreamObserverI {
+public:
+    virtual ~TCPSStreamObserverI() {}
+    /** @p stream just registered. May call back into the service. */
+    virtual void OnStreamRegistered(TCPSServiceStream *stream) = 0;
+    /** @p stream is leaving (it is still valid during the call). */
+    virtual void OnStreamUnregistered(TCPSServiceStream *stream) = 0;
+};
+
+} // namespace MARTe
+
+#endif // TCPS_STREAM_TAP_I_H_