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/io_utils/pibroadcast.cpp

@@ -21,6 +21,8 @@
 
 #include "piliterals_time.h"
 
+#ifndef PIP_NO_SOCKET
+
 /** \class PIBroadcast
  * \brief Broadcast for all interfaces, including loopback
  *
@@ -43,7 +45,7 @@
  *
  */
 
-#define MULTICAST_TTL 4
+#  define MULTICAST_TTL 4
 
 
 PIBroadcast::PIBroadcast(bool send_only): PIThread(), PIEthUtilBase() {
@@ -205,8 +207,8 @@ void PIBroadcast::initAll(PIVector<PINetworkAddress> al) {
 
 void PIBroadcast::send(const PIByteArray & data) {
 	/*if (!isRunning()) {
-		reinit();
-		PIThread::start(3000);
+	    reinit();
+	    PIThread::start(3000);
 	}*/
 	PIByteArray cd = cryptData(data);
 	if (cd.isEmpty()) return;
@@ -268,3 +270,5 @@ void PIBroadcast::run() {
 	if (ac || r) reinit();
 	if (ac) addressesChanged();
 }
+
+#endif // PIP_NO_SOCKET