feat(FN-1862): add completion state tracking for onboarding

- Add markOnboardingCompleted() to set completedAt timestamp when user finishes onboarding
- Add isOnboardingCompleted() to check if onboarding was completed (vs dismissed)
- Update ModelOnboardingModal to call markOnboardingCompleted on successful completion
- Skip onboarding auto-open when already completed locally
- Add completion state tracking tests in ModelOnboardingModal.test.tsx
- Add model-onboarding-state unit tests
- Update useAuthOnboarding to check local completion state before auto-opening
- Document localStorage completion state tracking pattern in .fusion/memory.md

packages/dashboard/app/hooks/useProjectFileBrowser.ts

@@ -54,10 +54,9 @@ export function useProjectFileBrowser(rootPath: string, enabled: boolean): UsePr
         if (!cancelled) {
           setEntries(response.entries);
         }
-      } catch (err: unknown) {
+      } catch (err: any) {
         if (!cancelled) {
-          const message = err instanceof Error ? err.message : String(err);
-          setError(message || "Failed to load files");
+          setError(err.message || "Failed to load files");
           setEntries([]);
         }
       } finally {