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/code/picodeparser.cpp

@@ -153,6 +153,7 @@ bool PICodeParser::isEnum(const PIString & name) {
 }
 
 
+#ifndef PIP_NO_FILESYSTEM
 bool PICodeParser::parseFileInternal(const PIString & file, bool follow_includes) {
 	if (proc_files[file]) return true;
 	with_includes = follow_includes;
@@ -178,6 +179,7 @@ bool PICodeParser::parseFileInternal(const PIString & file, bool follow_includes
 	piCout << "parsing" << f.path() << "done";
 	return ret;
 }
+#endif // PIP_NO_FILESYSTEM
 
 
 void PICodeParser::clear() {