2V1-d: offline login -> select -> loading against a fake 40250 server

port.login_flow drives the real 40250 root scripts through the ported
CPythonNetworkStream and CAccountConnector against a loopback auth + game
server built from net/classic (wire layouts, sequence table, cipher) that
answers like the 40250 desc.cpp/input*.cpp: handshake, key agreement,
LOGIN3/AUTH_SUCCESS, LOGIN2, the character list, DirectEnter reconnect,
CHARACTER_SELECT, the loading packets and CLIENT_VERSION, with every
sequence byte checked.

- NetStream::ActivateCipher decrypts ciphertext already buffered behind
  KEY_AGREEMENT_COMPLETED (PORT)
- CPythonApplication is final (PORT): no application object exists on the
  platform yet, so its virtual overrides must be called directly
- app.GetTime (GetGlobalTime) and camera/center-position stubs
- SendClientVersionPacket verbatim in the PhaseGame stand-in

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

extension/src/platform/UserInterface/PythonApplication.cpp

@@ -49,6 +49,15 @@ void CPythonApplication::Abort()
 	PythonBoot::AppRequestQuit();
 }
 void CPythonApplication::SetMinFog(float) { MT_PLATFORM_STUB(); }
+// In 40250 Process() copies CTimer::GetCurrentSecond() into m_fGlobalTime right after Advance() and
+// this returns it. PORT: no member to hold it; the timer only advances in Process(), so reading it
+// here gives the same value.
+float CPythonApplication::GetGlobalTime() { return CTimer::Instance().GetCurrentSecond(); }
+// Camera (2V3).
+void CPythonApplication::SetEventCamera(const SCameraSetting&) { MT_PLATFORM_STUB(); }
+void CPythonApplication::SetDefaultCamera() { MT_PLATFORM_STUB(); }
+// In 40250 this stores m_v3CenterPosition for the game view (introselect.py sets it on the character list).
+void CPythonApplication::SetCenterPosition(float, float, float) { MT_PLATFORM_STUB(); }
 void CPythonApplication::SetFrameSkip(bool) { MT_PLATFORM_STUB(); }
 // PORT: 40250 creates the Win32 window, the D3D8 device, cursors, sound, keyboard, the net device,
 // fonts and the IME here. The Godot window and its canvas are the device on this platform and they