Redraw the in-game menu with the game's own interface textures, and bring in the launcher's save import and faster builds.

In-game menu: the settings window, its tabs, rows, buttons and cursor, the performance overlay and the Preparing
shaders box are drawn with the game's interface textures where the RomFS holds them (runtime/ui/menu_skin.cpp,
perf_panel.cpp; plain shapes until they are decoded). Restart joins Continue and Quit, each behind a confirmation;
VSync is an on/off switch; DLSS is listed only on NVIDIA GPUs; the menu sounds are quieter; Picture shape is gone and
the setting descriptions are shorter; edge cases of input, layout and fonts are fixed. tools/menu_preview.py draws the
menu without the game.

Launcher: Import Saves takes a save from the game folder's saves/ folder or one the player picks; downloads fall back
to Windows' own certificate check when Python's refuses a server; updates are faster; the title bar is drawn in the
window and Navi is every icon. tools/make_game.py builds with CLANG64's clang where the launcher installed it, packs
the RomFS beside the lift and the compile, takes a prebuilt runtime, and compiles the game's resources without cmd.exe,
so a user folder with a space in its name builds.

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

docs/README-BuildKit.md

@@ -49,9 +49,9 @@ With extracted folders instead, use `--exefs "C:\path\exefs" --romfs "C:\path\ro
 check that your dump is the right version, add `--check` (it builds nothing).
 
 The build checks the version, unpacks the program files, packs the 26 GB RomFS image (every file is checked against
-the dump's own checksums), turns the game's code into C and compiles it (about 6 minutes on a 16-thread Ryzen 7; longer on fewer cores),
-then prepares every one of the game's shaders for your graphics card (about 5 more minutes), so the game does not stop
-to compile shaders while you play.
+the dump's own checksums) while it turns the game's code into C and compiles it (about 6 minutes on a 16-thread
+Ryzen 7; longer on fewer cores), then prepares every one of the game's shaders for your graphics card (about 5 more
+minutes), so the game does not stop to compile shaders while you play. The game it builds is for this PC's processor.
 You can use your PC meanwhile. If it stops,
 run the same command again: finished steps are skipped.
 
@@ -62,7 +62,9 @@ When it says `finished`, start `C:\Games\Ocarina\ocarina.exe`. You can delete `C
 
 - **F1** opens the settings menu. Settings are saved in `nx2navi.ini` beside the game; saves go to `profile\`.
 - Every shader was prepared during the build. After an update of your graphics driver, the next start shows
-  "Preparing shaders" once while the driver rebuilds them.
+  "Preparing shaders" once while the driver rebuilds them. With a driver that has Vulkan's graphics pipeline library
+  it lasts at most about 20 seconds once the shaders are translated, and the remaining pipelines are built in the
+  background while you play.
 - **Screen** in the menu has Upscaling (DLSS on NVIDIA RTX cards, FSR 3.1 on any card), Frame generation (FSR 3.1; it
   needs DLSS or FSR 3.1 upscaling on), HDR (Native is the game's own HDR; turn HDR on in Windows first) and the
   resolution. Those marked "after restart" take effect when the game starts again.