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/io_utils/pifiletransfer.h

@@ -31,7 +31,7 @@
 #include "pibasetransfer.h"
 #include "pidir.h"
 
-#ifndef PIP_NO_FILESYSTEM
+#ifdef PIP_HAS_FILESYSTEM
 #  define __PIFILETRANSFER_VERSION 2
 
 
@@ -263,6 +263,6 @@ inline PICout operator<<(PICout s, const PIFileTransfer::PFTFileInfo & v) {
 	s.restoreControls();
 	return s;
 }
-#endif // PIP_NO_FILESYSTEM
+#endif // PIP_HAS_FILESYSTEM
 
 #endif // PIFILETRANSFER_H