impeccable-25-rule-deterministic-design-scanner

The Impeccable library (github.com/pbakaus/impeccable) provides a 3,590-line JS engine with 25 detection rules across two categories: 13 AI-slop tells (Inter/default fonts, purple/blue gradients, glassmorphism, pill badges, gradient text, emoji in UI, placeholder copy, etc.) and 12 general quality rules (contrast, spacing, hover states, z-index chaos, responsive gaps). This is zero-LLM-cost deterministic scanning — wire as a PostToolUse hook on Write/Edit to .html/.css/.tsx/.jsx/.svelte/.astro files via npx impeccable detect --json <file>. Fills the gap where all current frontend quality assessment is LLM-based and probabilistic.