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/thread/pireadwritelock.cpp

@@ -1,7 +1,7 @@
 /*
     PIP - Platform Independent Primitives
-	PIReadWriteLock, PIReadLocker, PIWriteLocker
-	Ivan Pelipenko peri4ko@yandex.ru
+    PIReadWriteLock, PIReadLocker, PIWriteLocker
+    Ivan Pelipenko peri4ko@yandex.ru
 
     This program is free software: you can redistribute it and/or modify
     it under the terms of the GNU Lesser General Public License as published by
@@ -151,6 +151,8 @@
 
 #include "pireadwritelock.h"
 
+#ifndef PIP_NO_THREADS
+
 
 PIReadWriteLock::PIReadWriteLock() {}
 
@@ -232,3 +234,5 @@ void PIReadWriteLock::unlockRead() {
 	--reading;
 	var.notifyAll();
 }
+
+#endif // PIP_NO_THREADS