refactor: rename PIP_NO_\* to PIP_HAS_\* with inverted logic

All feature flags now use positive naming (enabled by default):
- PIP_HAS_FILESYSTEM, PIP_HAS_THREADS, PIP_HAS_SOCKET
- PIP_HAS_PROCESS, PIP_HAS_DYNLIB, PIP_HAS_FFT, PIP_HAS_SERIAL

Preprocessor guards inverted:
- #ifndef PIP_NO_X → #ifdef PIP_HAS_X
- #ifdef PIP_NO_X → #ifndef PIP_HAS_X

CMake options default ON instead of OFF.
Platform blocks set flags OFF to disable features.

85 files transformed via Python script + 2 manual fixes.

libs/main/application/pilog.h

@@ -29,8 +29,8 @@
 #include "piiostream.h"
 #include "pithread.h"
 
-#ifndef PIP_NO_THREADS
-#  ifndef PIP_NO_FILESYSTEM
+#ifdef PIP_HAS_THREADS
+#  ifdef PIP_HAS_FILESYSTEM
 
 //! \~\ingroup Application
 //! \~\brief
@@ -187,7 +187,7 @@ private:
 	int part_number = -1, cout_id = -1;
 };
 
-#  endif // PIP_NO_FILESYSTEM
-#endif   // PIP_NO_THREADS
+#  endif // PIP_HAS_FILESYSTEM
+#endif   // PIP_HAS_THREADS
 
 #endif // PIlog_H