Detect native-Linux Stardew Valley, default executables to no-Proton

Add IPluginGame::isNativeLinux() (virtual, default false) so a plugin
can advertise that the discovered installation is a native Linux build.
Bound through the Python plugin trampoline so basic_games subclasses can
override it.

Stardew Valley plugin: when the install dir contains the StardewValley
launcher script and no Stardew Valley.exe, report isNativeLinux=true and
return Linux-side binary names (StardewValley, StardewModdingAPI). Also
fix GameDataPath to "Mods" — Linux ships the SMAPI mods dir with a
capital M.

ExecutablesList::getPluginExecutables: skip the UseProton flag when the
plugin reports native Linux, so the spawn path falls into launchDirect()
and the game runs without a Wine prefix.

1 files changed, 4 insertions, 0 deletions

diff --git a/libs/plugin_python/src/mobase/wrappers/pyplugins.h b/libs/plugin_python/src/mobase/wrappers/pyplugins.h
index 17f7ab5..ce9a911 100644
--- a/libs/plugin_python/src/mobase/wrappers/pyplugins.h
+++ b/libs/plugin_python/src/mobase/wrappers/pyplugins.h
@@ -385,6 +385,10 @@ namespace mo2::python {
         {
             PYBIND11_OVERRIDE_PURE(bool, IPluginGame, isInstalled, );
         }
+        bool isNativeLinux() const override
+        {
+            PYBIND11_OVERRIDE(bool, IPluginGame, isNativeLinux, );
+        }
         QIcon gameIcon() const override
         {
             PYBIND11_OVERRIDE_PURE(QIcon, IPluginGame, gameIcon, );