Fix dependency installation not respecting mod loader (#4751)

* Fix dependency installation not respecting mod loader

* fix

Author: aecsocket

apps/app-frontend/src/store/install.js

@@ -42,11 +42,24 @@ export const useInstall = defineStore('installStore', {
 })
 
 export const findPreferredVersion = (versions, project, instance) => {
+	// When `project` is passed in from this stack trace:
+	// - `installVersionDependencies`
+	// - `install.js/install` - `installVersionDependencies` call
+	//
+	// ..then `project` is actually a `Dependency` struct of a cached `Version`.
+	// `Dependency` does not have a `project_type` field,
+	// so we default it to `mod`.
+	//
+	// If we don't default here, then this `.find` will ignore version/instance
+	// loader mismatches, and you'll end up e.g. installing NeoForge mods for a
+	// Fabric instance.
+	const projectType = project.project_type ?? 'mod'
+
 	// If we can find a version using strictly the instance loader then prefer that
 	let version = versions.find(
 		(v) =>
 			v.game_versions.includes(instance.game_version) &&
-			(project.project_type === 'mod' ? v.loaders.includes(instance.loader) : true),
+			(projectType === 'mod' ? v.loaders.includes(instance.loader) : true),
 	)
 
 	if (!version) {