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_utils/piconnection.h

@@ -379,6 +379,7 @@ public:
 	bool isEmpty() const { return device_modes.isEmpty(); }
 
 
+#ifndef PIP_NO_THREADS
 	//! \~english Returns diagnostics object for device or filter "full_path_name".
 	//! \~russian Возвращает объект диагностики для устройства или фильтра "full_path_name".
 	PIDiagnostics * diagnostic(const PIString & full_path_name) const;
@@ -386,6 +387,7 @@ public:
 	//! \~english Returns diagnostics object associated with device or filter "dev".
 	//! \~russian Возвращает объект диагностики, связанный с устройством или фильтром "dev".
 	PIDiagnostics * diagnostic(const PIIODevice * dev) const { return diags_.value(const_cast<PIIODevice *>(dev), 0); }
+#endif
 
 	//! \~english Writes "data" to device resolved by full path "full_path".
 	//! \~russian Записывает "data" в устройство, найденное по полному пути "full_path".
@@ -415,6 +417,7 @@ public:
 	//! \~russian Возвращает, работает ли общий пул устройств в режиме имитации.
 	static bool isFakeMode();
 
+#ifndef PIP_NO_THREADS
 	class PIP_EXPORT DevicePool: public PIThread {
 		PIOBJECT_SUBCLASS(DevicePool, PIThread);
 		friend void __DevicePool_threadReadDP(void * ddp);
@@ -456,6 +459,7 @@ public:
 		PIMap<PIString, DeviceData *> devices;
 		bool fake;
 	};
+#endif // PIP_NO_THREADS
 
 
 	//! \events
@@ -471,10 +475,12 @@ public:
 	//! \~russian Генерируется, когда фильтр "from" выдает пакет.
 	EVENT2(packetReceivedEvent, const PIString &, from, const PIByteArray &, data);
 
+#ifndef PIP_NO_THREADS
 	//! \fn void qualityChanged(const PIIODevice * device, PIDiagnostics::Quality new_quality, PIDiagnostics::Quality old_quality)
 	//! \~english Emitted when diagnostics quality of "device" changes.
 	//! \~russian Генерируется при изменении качества диагностики устройства "device".
 	EVENT3(qualityChanged, const PIIODevice *, dev, PIDiagnostics::Quality, new_quality, PIDiagnostics::Quality, old_quality);
+#endif
 
 	//! \}
 
@@ -496,7 +502,9 @@ private:
 	void rawReceived(PIIODevice * dev, const PIString & from, const PIByteArray & data);
 	void unboundExtractor(PIPacketExtractor * pe);
 	EVENT_HANDLER2(void, packetExtractorReceived, const uchar *, data, int, size);
+#ifndef PIP_NO_THREADS
 	EVENT_HANDLER2(void, diagQualityChanged, PIDiagnostics::Quality, new_quality, PIDiagnostics::Quality, old_quality);
+#endif
 
 	PIString devPath(const PIIODevice * d) const;
 	PIString devFPath(const PIIODevice * d) const;
@@ -509,6 +517,7 @@ private:
 		PIVector<PIIODevice *> devices;
 	};
 
+#ifndef PIP_NO_THREADS
 	class PIP_EXPORT Sender: public PITimer {
 		PIOBJECT_SUBCLASS(Sender, PIObject);
 
@@ -521,18 +530,24 @@ private:
 		PISystemTime int_;
 		void tick(int) override;
 	};
+#endif
 
 	PIMap<PIString, Extractor *> extractors;
+#ifndef PIP_NO_THREADS
 	PIMap<PIString, Sender *> senders;
+#endif
 	PIMap<PIString, PIIODevice *> device_names;
 	PIMap<PIIODevice *, PIIODevice::DeviceMode> device_modes;
 	PIMap<PIIODevice *, PIVector<PIPacketExtractor *>> bounded_extractors;
 	PIMap<PIIODevice *, PIVector<PIIODevice *>> channels_;
+#ifndef PIP_NO_THREADS
 	PIMap<PIIODevice *, PIDiagnostics *> diags_;
+#endif
 
 	static PIVector<PIConnection *> _connections;
 };
 
+#ifndef PIP_NO_THREADS
 void __DevicePool_threadReadDP(void * ddp);
 
 extern PIP_EXPORT PIConnection::DevicePool * __device_pool__;
@@ -544,6 +559,7 @@ public:
 };
 
 static __DevicePoolContainer__ __device_pool_container__;
+#endif // PIP_NO_THREADS
 
 
 #endif // PICONNECTION_H