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/system/pisystemtests.cpp

@@ -19,9 +19,9 @@
 
 #include "pisystemtests.h"
 
-#ifndef PIP_NO_FILESYSTEM
+#ifdef PIP_HAS_FILESYSTEM
 #  include "piconfig.h"
-#endif // !PIP_NO_FILESYSTEM
+#endif // PIP_HAS_FILESYSTEM
 
 
 namespace PISystemTests {
@@ -35,10 +35,10 @@ PISystemTestReader pisystestreader;
 
 
 PISystemTests::PISystemTestReader::PISystemTestReader() {
-#if !defined(WINDOWS) && !defined(PIP_NO_FILESYSTEM)
+#if !defined(WINDOWS) && defined(PIP_HAS_FILESYSTEM)
 	PIConfig conf(PIStringAscii("/etc/pip.conf"), PIIODevice::ReadOnly);
 	time_resolution_ns = conf.getValue(PIStringAscii("time_resolution_ns"), 1).toLong();
 	time_elapsed_ns    = conf.getValue(PIStringAscii("time_elapsed_ns"), 0).toLong();
 	usleep_offset_us   = conf.getValue(PIStringAscii("usleep_offset_us"), 60).toLong();
-#endif // !WINDOWS && !PIP_NO_FILESYSTEM
+#endif // !WINDOWS && PIP_HAS_FILESYSTEM
 }