Update architecture: package distribution supersedes forks

Record the move from a fork-based downstream model to versioned npm-package
consumption (GitHub Packages, @richiesnitch/ads3-design-system).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

ARCHITECTURE.md

@@ -6,7 +6,15 @@ This is the living architecture document for the ADS 3.0 design system. All stru
 
 ## 1. Overview
 
-ADS 3.0 Design System is a React component library implementing the ADS 3.0 (Adaptive Design System) design language. It provides tokens, primitives, and composite components as a shared foundation. Application-specific screens and domain logic belong in downstream forks of this repo.
+ADS 3.0 Design System is a React component library implementing the ADS 3.0 (Adaptive Design System) design language. It provides tokens, primitives, and composite components as a shared foundation. Application-specific screens and domain logic belong in **consuming applications**, not in this repo.
+
+### Distribution
+
+ADS is distributed as a **versioned npm package** consumed by downstream apps — not by forking this repo. (The earlier fork-based model has been superseded.)
+
+- Published to **GitHub Packages** as `@richiesnitch/ads3-design-system` from `Richiesnitch/ads3-design-system`; a publish-on-tag GitHub Action runs `build:lib` and `npm publish`.
+- Built via `npm run build:lib` (`vite.lib.config.ts`): bundles `src/index.ts` to ESM with React/react-dom externalised and internal `@/` imports resolved at build time; emits type declarations and copies `tokens.css` / `typography.css` into `dist/`.
+- Consumers import components from the package entry, `@richiesnitch/ads3-design-system/tokens` + `/typography` for the design-token CSS, and point Tailwind's `@source` at the built bundle to generate utilities. No `@/` alias or sibling-folder clone required.
 
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