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/application/pilog.h

@@ -29,6 +29,9 @@
 #include "piiostream.h"
 #include "pithread.h"
 
+#ifndef PIP_NO_THREADS
+#  ifndef PIP_NO_FILESYSTEM
+
 //! \~\ingroup Application
 //! \~\brief
 //! \~english High-level log
@@ -184,4 +187,7 @@ private:
 	int part_number = -1, cout_id = -1;
 };
 
-#endif
+#  endif // PIP_NO_FILESYSTEM
+#endif   // PIP_NO_THREADS
+
+#endif // PIlog_H