feat: lay the site out as a reading funnel

Five tabs from Start here to Contribute, a level on every page, a device picker on Get your files that lists every registered platform, and platform pages that open on where the files go, the command, the pack and how to check. FAQ and troubleshooting keep the questions asked before installing, the technical ones move to their own page, and getting started points to the pages that took its content.

tests/test_doc_pages.py

@@ -730,7 +730,8 @@ class RetroArchWindowsSystemFolder(unittest.TestCase):
     """Getting started gave %APPDATA%\\RetroArch\\system for the Windows
     installer. RetroArch's default is `:\\system`, the folder of
     retroarch.exe (platform_win32.c). %APPDATA% is where a retroarch.cfg
-    can live, and install.py reads it there."""
+    can live, and install.py reads it there. The RetroArch page of the site
+    states the folder now, from the guide data."""
 
     def test_page_and_installer_agree(self):
         import install
@@ -738,10 +739,26 @@ class RetroArchWindowsSystemFolder(unittest.TestCase):
         source = inspect.getsource(install)
         self.assertIn('ra_dir or exe_dir / "system"', source)
         self.assertTrue(str(install._os_default_dests("windows")["retroarch"]).replace("\\", "/").endswith("/system"))
-        section = _section(_page("getting-started.md"), "RetroArch")
+        from siteguides import GUIDES
+
+        guide = GUIDES["retroarch"]
+        section = "\n".join([*(path for _label, path in guide.folders), *guide.notes])
         self.assertNotIn("%APPDATA%\\RetroArch\\system", section)
         self.assertIn("`system\\` next to `retroarch.exe`", section)
 
+    def test_the_macos_folder_is_the_installers(self):
+        """The site gave Application Support/RetroArch/system for macOS. A
+        RetroArch left at its defaults reads ~/Documents/RetroArch/system
+        (platform_darwin.m), Application Support only for a portable or
+        Steam build, and install.py looks there in that order."""
+        import install
+        from siteguides import GUIDES
+
+        source = inspect.getsource(install._macos_retroarch_base)
+        self.assertIn('Path.home() / "Documents" / "RetroArch"', source)
+        folders = dict(GUIDES["retroarch"].folders)
+        self.assertEqual(folders["macOS"], "`~/Documents/RetroArch/system/`")
+
 
 if __name__ == "__main__":
     unittest.main()