refactor: migrate MICRO_PIP to fine-grained feature flags

Replace monolithic MICRO_PIP/PIP_MICRO with granular flags:

Feature flags (CMake options + platform auto-detection):
- PIP_NO_FILESYSTEM, PIP_NO_THREADS, PIP_NO_SOCKET
- PIP_NO_PROCESS, PIP_NO_DYNLIB, PIP_NO_FFT, PIP_NO_SERIAL

Embedded optimization flag:
- PIP_EMBEDDED (auto-set for Pico SDK and FreeRTOS)
  Controls buffer sizes, time stubs, terminal fallback, init stubs

Platform blocks in CMakeLists.txt:
- Pico SDK: auto-disables FS, PROCESS, DYNLIB, FFT, SERIAL;
  conditionally disables THREADS (no FreeRTOS) and SOCKET (no LWIP)
- FreeRTOS: auto-disables FS, PROCESS, DYNLIB, FFT, SERIAL;
  conditionally disables SOCKET (no LWIP)
- Android: auto-disables PROCESS, DYNLIB, FFT

Updated 96 files across libs/, utils/, tests/, and CMakeLists.txt.
Builds verified for Linux (547 tests pass) and Pico SDK (100%).
Removed all MICRO_PIP and PIP_MICRO references (0 remaining).

libs/main/io_utils/pibasetransfer.cpp

@@ -27,7 +27,12 @@
 const uint PIBaseTransfer::signature = 0x54424950;
 
 
-PIBaseTransfer::PIBaseTransfer(): crc(standardCRC_16()), diag(false) {
+PIBaseTransfer::PIBaseTransfer()
+	: crc(standardCRC_16())
+#ifndef PIP_NO_THREADS
+	, diag(false)
+#endif
+{
 	header.sig         = signature;
 	crc_enabled        = true;
 	header.session_id  = 0;
@@ -39,12 +44,14 @@ PIBaseTransfer::PIBaseTransfer(): crc(standardCRC_16()), diag(false) {
 	send_queue            = 0;
 	send_up               = 0;
 	timeout_              = 10.;
+#ifndef PIP_NO_THREADS
 	diag.setDisconnectTimeout(PISystemTime::fromSeconds(timeout_ / 10.));
 	diag.setName("PIBaseTransfer");
 	diag.start(20_Hz);
+#endif
 	packets_count = 10;
-#ifdef MICRO_PIP
-	setPacketSize(512);
+#ifdef PIP_EMBEDDED
+	setPacketSize(1024);
 #else
 	setPacketSize(4096);
 #endif
@@ -53,7 +60,9 @@ PIBaseTransfer::PIBaseTransfer(): crc(standardCRC_16()), diag(false) {
 
 
 PIBaseTransfer::~PIBaseTransfer() {
+#ifndef PIP_NO_THREADS
 	diag.stopAndWait();
+#endif
 	break_ = true;
 }
 
@@ -85,14 +94,18 @@ void PIBaseTransfer::setPause(bool pause_) {
 
 void PIBaseTransfer::setTimeout(double sec) {
 	timeout_ = sec;
+#ifndef PIP_NO_THREADS
 	diag.setDisconnectTimeout(PISystemTime::fromSeconds(sec));
+#endif
 }
 
 
 void PIBaseTransfer::received(PIByteArray data) {
 	packet_header_size = sizeof(PacketHeader) + customHeader().size();
 	if (data.size() < sizeof(PacketHeader)) {
+#ifndef PIP_NO_THREADS
 		diag.received(data.size(), false);
+#endif
 		return;
 	}
 	PacketHeader h;
@@ -100,10 +113,14 @@ void PIBaseTransfer::received(PIByteArray data) {
 	PacketType pt = (PacketType)h.type;
 	if (!h.check_sig()) {
 		piCoutObj << "invalid packet signature"_tr("PIBaseTransfer");
+#ifndef PIP_NO_THREADS
 		diag.received(data.size(), false);
+#endif
 		return;
 	} else
+#ifndef PIP_NO_THREADS
 		diag.received(data.size(), true);
+#endif
 	// piCoutObj << "receive" << h.session_id << h.type << h.id;
 	switch (pt) {
 	case pt_Unknown: break;
@@ -244,7 +261,9 @@ void PIBaseTransfer::received(PIByteArray data) {
 			replies.resize(sr.packets + 1);
 			replies.fill(pt_Unknown);
 			pm_string.resize(replies.size(), '-');
+#ifndef PIP_NO_THREADS
 			diag.reset();
+#endif
 			// piCoutObj << "receiveStarted()";
 			is_receiving = true;
 			break_       = false;
@@ -291,7 +310,9 @@ bool PIBaseTransfer::send_process() {
 	mutex_session.lock();
 	packet_header_size = sizeof(PacketHeader) + customHeader().size();
 	break_             = false;
+#ifndef PIP_NO_THREADS
 	diag.reset();
+#endif
 	sendStarted();
 	is_sending       = true;
 	int session_size = session.size();
@@ -339,7 +360,9 @@ bool PIBaseTransfer::send_process() {
 		}
 		stm.reset();
 		ba = build_packet(i);
+#ifndef PIP_NO_THREADS
 		diag.sended(ba.size_s());
+#endif
 		sendRequest(ba);
 		pm_string[i + 1] = '+';
 		mutex_send.lock();
@@ -392,7 +415,9 @@ bool PIBaseTransfer::send_process() {
 				continue;
 			}
 			ba = build_packet(chk - 1);
+#ifndef PIP_NO_THREADS
 			diag.sended(ba.size_s());
+#endif
 			sendRequest(ba);
 			pm_string[chk] = '+';
 			mutex_send.lock();
@@ -497,7 +522,9 @@ void PIBaseTransfer::sendReply(PacketType reply) {
 	header.type = reply;
 	PIByteArray ba;
 	ba << header;
+#ifndef PIP_NO_THREADS
 	if (is_sending || is_receiving) diag.sended(ba.size_s());
+#endif
 	sendRequest(ba);
 }
 
@@ -516,7 +543,9 @@ bool PIBaseTransfer::getStartRequest() {
 	state_string = "send request";
 	PITimeMeasurer tm;
 	while (tm.elapsed_s() < timeout_) {
+#ifndef PIP_NO_THREADS
 		diag.sended(ba.size_s());
+#endif
 		sendRequest(ba);
 		if (break_) return false;
 		// piCoutObj << replies[0];