test(appd): add QueryInstalledApps dispatch test; fix weft-runtime test race

main.rs: add dispatch_query_installed_returns_installed_apps to verify
the QueryInstalledApps arm returns Response::InstalledApps.

wsl-test.sh: run weft-runtime tests with --test-threads=1 to prevent
the WEFT_APP_STORE env var race between package_store_roots_includes_
system_path and package_store_roots_uses_weft_app_store_when_set.

crates/weft-appd/src/main.rs

@@ -497,6 +497,13 @@ mod tests {
         assert!(matches!(reg.state(42), AppStateKind::NotFound));
     }
 
+    #[tokio::test]
+    async fn dispatch_query_installed_returns_installed_apps() {
+        let reg = make_registry();
+        let resp = dispatch(Request::QueryInstalledApps, &reg).await;
+        assert!(matches!(resp, Response::InstalledApps { .. }));
+    }
+
     #[test]
     fn scan_installed_apps_finds_valid_packages() {
         use std::fs;

scripts/wsl-test.sh

@@ -32,7 +32,7 @@ cargo test -p weft-appd 2>&1
 
 echo ""
 echo "==> cargo test -p weft-runtime"
-cargo test -p weft-runtime 2>&1
+cargo test -p weft-runtime -- --test-threads=1 2>&1
 
 echo ""
 echo "==> cargo test -p weft-pack"