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/console/pikbdlistener.cpp

@@ -18,7 +18,7 @@
 */
 #include "pikbdlistener.h"
 
-#ifndef PIP_NO_THREADS
+#ifdef PIP_HAS_THREADS
 
 #  include "piincludes_p.h"
 #  include "piliterals.h"
@@ -590,4 +590,4 @@ void PIKbdListener::setActive(bool yes) {
 	}
 }
 
-#endif // PIP_NO_THREADS
+#endif // PIP_HAS_THREADS

libs/main/console/pikbdlistener.h

@@ -27,7 +27,7 @@
 
 #include "pibase.h"
 
-#ifndef PIP_NO_THREADS
+#ifdef PIP_HAS_THREADS
 
 #  include "pithread.h"
 #  include "pitime.h"
@@ -381,5 +381,5 @@ REGISTER_PIVARIANTSIMPLE(PIKbdListener::KeyEvent)
 REGISTER_PIVARIANTSIMPLE(PIKbdListener::MouseEvent)
 REGISTER_PIVARIANTSIMPLE(PIKbdListener::WheelEvent)
 
-#endif // PIP_NO_THREADS
+#endif // PIP_HAS_THREADS
 #endif // PIKBDLISTENER_H