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/piplatform.h

@@ -74,12 +74,6 @@
 //! \~russian Определяется для целевых сборок FreeBSD.
 #  define FREE_BSD
 
-//! \~\ingroup Core
-//! \~\brief
-//! \~english Defined for reduced embedded PIP builds.
-//! \~russian Определяется для облегченных встраиваемых сборок PIP.
-#  define MICRO_PIP
-
 //! \~\ingroup Core
 //! \~\brief
 //! \~english Defined when the target architecture is 32-bit.
@@ -153,23 +147,24 @@
 #ifdef PIP_FREERTOS
 #  define FREERTOS
 #endif
-#ifdef MICRO_PIP
-#  ifndef FREERTOS
-#	define PIP_NO_THREADS
-#  endif
-#  ifndef LWIP
-#    define PIP_NO_SOCKET
-#  endif
+#ifdef PICO_SDK
 #  define PISERIAL_NO_PINS
 #endif
+#ifdef FREERTOS
+#  ifndef PISERIAL_NO_PINS
+#	define PISERIAL_NO_PINS
+#  endif
+#endif
 #ifndef WINDOWS
 #  ifndef QNX
 #	ifndef FREE_BSD
 #	  ifndef MAC_OS
 #		ifndef ANDROID
 #		  ifndef BLACKBERRY
-#			ifndef MICRO_PIP
-#			  define LINUX
+#			ifndef FREERTOS
+#			  ifndef PICO_SDK
+#				define LINUX
+#			  endif
 #			endif
 #		  endif
 #		endif