Update build scripts to pass target environment variable for backend processes

- Modified `build.rs` to pass the `TARGET` environment variable as `APP_TARGET` to `lib.rs`, ensuring consistent access to the target architecture during the build process.
- Updated references in `lib.rs` to use `APP_TARGET` instead of `TARGET`, improving clarity and maintainability in backend process spawning.

Author: Administrator

client/src-tauri/build.rs

@@ -1,3 +1,5 @@
 fn main() {
+  // Pass TARGET to lib.rs - Cargo sets TARGET in build scripts but not always at compile time
+  println!("cargo:rustc-env=APP_TARGET={}", std::env::var("TARGET").unwrap_or_else(|_| "unknown".into()));
   tauri_build::build()
 }

client/src-tauri/src/lib.rs

@@ -52,7 +52,7 @@ fn spawn_backend_process(app: Option<&tauri::AppHandle>) -> Result<BackendProces
       .path()
       .resource_dir()
       .map_err(|e| format!("resource_dir: {}", e))?;
-    let target = env!("TARGET");
+    let target = env!("APP_TARGET");
     let sidecar_name = format!(
       "backend-{}{}",
       target,
@@ -134,7 +134,7 @@ fn spawn_backend_build(
       .path()
       .resource_dir()
       .map_err(|e| format!("resource_dir: {}", e))?;
-    let target = env!("TARGET");
+    let target = env!("APP_TARGET");
     let sidecar_name = format!(
       "backend-{}{}",
       target,