fix: tag badges and buttons using bg-accent with unreadable text

bg-accent (#f97316 orange) with text-muted-foreground (#848b9b gray)
is nearly invisible. Replaced with bg-elevated + border pattern for
readable contrast across TagBadges, StepForm, StepDetailModal, and
StepLibraryBrowser. Also fixed emerald → success-dim token.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/src/components/step-library/StepDetailModal.tsx

@@ -208,8 +208,8 @@ export function StepDetailModal({ stepId, onClose, onInsert }: StepDetailModalPr
                             className={cn(
                               'flex items-center gap-1 rounded px-2 py-1 text-xs transition-colors',
                               copiedCommandIndex === index
-                                ? 'bg-emerald-400/10 text-emerald-400'
-                                : 'bg-accent text-muted-foreground hover:bg-accent hover:text-foreground'
+                                ? 'bg-success-dim text-success'
+                                : 'border border-border bg-[var(--color-bg-elevated)] text-muted-foreground hover:text-foreground hover:border-[var(--color-border-hover)]'
                             )}
                           >
                             {copiedCommandIndex === index ? (