feat: add NVIDIA Prime environment variables for Linux hybrid graphics (#155)HEADmain

## Summary
- Inject __NV_PRIME_RENDER_OFFLOAD=1 and
__GLX_VENDOR_LIBRARY_NAME=nvidia environment variables when launching
Minecraft on Linux
- Enables discrete GPU usage on Linux systems with hybrid graphics
(NVIDIA + Intel/AMD)
- Only applies on Linux via #[cfg(target_os = "linux")]

## Changes
- Modified src-tauri/src/main.rs to inject NVIDIA Prime environment
variables before spawning the Java process

## Test Plan
- On a Linux system with hybrid graphics (NVIDIA + Intel/AMD), launch
the game and verify the discrete GPU is being used
- Can check with nvidia-smi or glxinfo to confirm GPU usage

Closes #154

## Summary by Sourcery

Inject GPU-related environment variables when launching the game on
Linux to support hybrid graphics configurations.

New Features:
- Enable discrete GPU usage on Linux hybrid graphics systems by setting
NVIDIA Prime and AMD DRI_PRIME environment variables before starting the
game process.

Enhancements:
- Log when GPU environment variables are injected on Linux to aid
debugging of hybrid graphics setups.

---------

Co-authored-by: 简律纯 <i@jyunko.cn>
Co-authored-by: sourcery-ai[bot] <58596630+sourcery-ai[bot]@users.noreply.github.com>

1 files changed, 31 insertions, 0 deletions

diff --git a/src-tauri/src/main.rs b/src-tauri/src/main.rs
index 7f7c4c0..952d250 100644
--- a/src-tauri/src/main.rs
+++ b/src-tauri/src/main.rs
@@ -862,6 +862,37 @@ async fn start_game(
         );
     }
 
+    // On Linux, inject GPU environment variables for hybrid graphics support
+    // but do not override values that are already set in the environment.
+    #[cfg(target_os = "linux")]
+    {
+        let mut injected_any = false;
+
+        // NVIDIA Prime Render Offload - enables discrete NVIDIA GPU on hybrid systems
+        if std::env::var_os("__NV_PRIME_RENDER_OFFLOAD").is_none() {
+            command.env("__NV_PRIME_RENDER_OFFLOAD", "1");
+            injected_any = true;
+        }
+
+        if std::env::var_os("__GLX_VENDOR_LIBRARY_NAME").is_none() {
+            command.env("__GLX_VENDOR_LIBRARY_NAME", "nvidia");
+            injected_any = true;
+        }
+
+        // AMD DRI_PRIME - enables discrete AMD GPU on hybrid systems
+        if std::env::var_os("DRI_PRIME").is_none() {
+            command.env("DRI_PRIME", "1");
+            injected_any = true;
+        }
+
+        if injected_any {
+            emit_log!(
+                window,
+                "Injected default GPU environment variables for Linux (NVIDIA Prime & AMD DRI_PRIME, only where unset)".to_string()
+            );
+        }
+    }
+
     // Spawn and handle output
     let mut child = command
         .spawn()