builder: retain Cargo config for run and correct acceptance checks

host/src/builder/mod.rs

@@ -123,12 +123,15 @@ impl Builder {
             b"Signature: 8a477f597d28d172789f06886806bc55\n",
         )?;
         std::fs::write(base.join("last-used"), [])?;
-        let cwd = source.join(
-            world_cwd
-                .strip_prefix(&workspace)
-                .expect("workspace is an ancestor of cwd")
-                .trim_start_matches('/'),
-        );
+        let relative = world_cwd
+            .strip_prefix(&workspace)
+            .expect("workspace is an ancestor of cwd")
+            .trim_start_matches('/');
+        let cwd = if relative.is_empty() {
+            source.clone()
+        } else {
+            source.join(relative)
+        };
         let mut fetch = Command::new("cargo");
         if action == "add" {
             fetch.args(&request.argv).arg("--dry-run");
@@ -274,7 +277,6 @@ impl Builder {
                 }
             }
             let split = args.iter().position(|a| a == "--").unwrap_or(args.len());
-            cmd.args(&args[..split]);
             if action == "run" {
                 cmd.arg("--config").arg(format!(
                     "target.wasm32-wasip2.runner=[{:?},{:?}]",
@@ -282,6 +284,8 @@ impl Builder {
                     tools.join("run.nu")
                 ));
             }
+            // Keep all global config flags before the subcommand so Cargo retains them.
+            cmd.args(&args[..split]);
             if compiles {
                 cmd.args([
                     "--target",