fix(FN-1031): replace var(--error) with var(--color-error) in project components

- Fix incorrect CSS token var(--error) → var(--color-error) in ProjectCard, ProjectHealthBadge, and ProjectSelector
- Add regression test suite (ProjectThemeTokens.test.tsx) covering all project components for correct token usage
- Ensures consistency with the design system's CSS custom property naming convention

packages/dashboard/app/components/ProjectCard.tsx

@@ -15,7 +15,7 @@ export interface ProjectCardProps {
 const STATUS_CONFIG: Record<ProjectStatus, { label: string; color: string; icon: typeof Play }> = {
   active: { label: "Active", color: "var(--success)", icon: Play },
   paused: { label: "Paused", color: "var(--warning)", icon: Pause },
-  errored: { label: "Error", color: "var(--error)", icon: AlertCircle },
+  errored: { label: "Error", color: "var(--color-error)", icon: AlertCircle },
   initializing: { label: "Initializing", color: "var(--info)", icon: Loader2 },
 };