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_devices/pipeer.h

@@ -34,10 +34,11 @@
 //! \~russian Именованный сетевой пир, построенный поверх %PIIODevice.
 //! \~\details
 //! \~english
-//! The class discovers peers, routes packets by peer name and can expose a trusted-peer stream through inherited \a read() and \a write().
+//! The class discovers peers, routes packets by peer name and can expose a trusted-peer stream through inherited \a read() и \a write().
 //! \~russian
 //! Класс обнаруживает пиры, маршрутизирует пакеты по имени пира и может предоставлять поток trusted-peer через унаследованные \a read() и
 //! \a write().
+#ifndef PIP_NO_SOCKET
 class PIP_EXPORT PIPeer: public PIIODevice {
 	PIIODEVICE(PIPeer, "peer");
 
@@ -436,6 +437,6 @@ BINARY_STREAM_READ(PIPeer::PeerInfo) {
 	s >> v.name >> v.addresses >> v.dist >> v.neighbours >> v.cnt >> v.time;
 	return s;
 }
-
+#endif // PIP_NO_SOCKET
 
 #endif // PIPEER_H