feat: add shared @sexy.pivoine.art/types package and fix type safety across frontend/backend

- Create packages/types with shared TypeScript domain model interfaces (User, Video, Model, Article, Comment, Recording, etc.)
- Wire both frontend and backend packages to use @sexy.pivoine.art/types via workspace:*
- Update backend Pothos objectRef types to use shared interfaces instead of inline types
- Update frontend $lib/types.ts to re-export from shared package
- Fix all type errors introduced by more accurate nullable types (avatar/banner as string|null UUIDs, author nullable, events/device_info as object[])
- Add artist_name to comment user select in backend resolver
- Widen utility function signatures (getAssetUrl, getUserInitials, calcReadingTime) to accept null/undefined

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

CLAUDE.md

@@ -0,0 +1,94 @@
+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Overview
+
+`sexy.pivoine.art` is a self-hosted adult content platform (18+) built as a pnpm monorepo with three packages: `frontend` (SvelteKit 5), `backend` (Fastify + GraphQL), and `buttplug` (hardware integration via WebBluetooth/WASM).
+
+## Common Commands
+
+Run from the repo root unless otherwise noted.
+
+```bash
+# Development
+pnpm dev:data        # Start postgres & redis via Docker
+pnpm dev:backend     # Start backend on http://localhost:4000
+pnpm dev             # Start backend + frontend (frontend on :3000)
+
+# Linting & Formatting
+pnpm lint            # ESLint across all packages
+pnpm lint:fix        # Auto-fix ESLint issues
+pnpm format          # Prettier format all files
+pnpm format:check    # Check formatting without changes
+
+# Build
+pnpm build:frontend  # SvelteKit production build
+pnpm build:backend   # Compile backend TypeScript to dist/
+
+# Database migrations (from packages/backend/)
+pnpm migrate         # Run pending Drizzle migrations
+```
+
+## Architecture
+
+### Monorepo Layout
+
+```
+packages/
+  frontend/   # SvelteKit 2 + Svelte 5 + Tailwind CSS 4
+  backend/    # Fastify v5 + GraphQL Yoga v5 + Drizzle ORM
+  buttplug/   # TypeScript/Rust hybrid, compiles to WASM
+```
+
+### Backend (`packages/backend/src/`)
+
+- **`index.ts`** — Fastify server entry: registers plugins (CORS, multipart, static), mounts GraphQL at `/graphql`, serves transformed assets at `/assets/:id`
+- **`graphql/builder.ts`** — Pothos schema builder (code-first GraphQL)
+- **`graphql/context.ts`** — Injects `currentUser` from Redis session into every request
+- **`lib/auth.ts`** — Session management: `nanoid(32)` token stored in Redis with 24h TTL, set as httpOnly cookie
+- **`db/schema/`** — Drizzle ORM table definitions (users, videos, files, comments, gamification, etc.)
+- **`migrations/`** — SQL migration files managed by Drizzle Kit
+
+### Frontend (`packages/frontend/src/`)
+
+- **`lib/api.ts`** — GraphQL client (graphql-request)
+- **`lib/services.ts`** — All API calls (login, videos, comments, models, etc.)
+- **`lib/types.ts`** — Shared TypeScript types
+- **`hooks.server.ts`** — Auth guard: reads session cookie, fetches `me` query, redirects if needed
+- **`routes/`** — SvelteKit file-based routing: `/`, `/login`, `/signup`, `/me`, `/models`, `/models/[slug]`, `/videos`, `/play/[slug]`, `/magazine`, `/leaderboard`
+
+### Asset Pipeline
+
+Backend serves images with server-side Sharp transforms, cached to disk as WebP. Presets: `mini` (80×80), `thumbnail` (300×300), `preview` (800px wide), `medium` (1400px wide), `banner` (1600×480 cropped).
+
+### Gamification
+
+Points + achievements system tracked in `user_points` and `user_stats` tables. Logic in `packages/backend/src/lib/gamification.ts` and the `gamification` resolver.
+
+## Code Style
+
+- **TypeScript strict mode** in all packages
+- **ESLint flat config** (`eslint.config.js` at root) — `any` is allowed but discouraged; enforces consistent type imports
+- **Prettier**: 2-space indent, trailing commas, 100-char line width, Svelte plugin
+- Migrations folder (`packages/backend/src/migrations/`) is excluded from lint
+
+## Environment Variables (Backend)
+
+| Variable | Purpose |
+|----------|---------|
+| `DATABASE_URL` | PostgreSQL connection string |
+| `REDIS_URL` | Redis connection string |
+| `COOKIE_SECRET` | Session cookie signing |
+| `CORS_ORIGIN` | Frontend origin URL |
+| `UPLOAD_DIR` | File storage path |
+| `SMTP_HOST/PORT/EMAIL_FROM` | Email (Nodemailer) |
+
+## Docker
+
+```bash
+docker compose up -d          # Start all services (postgres, redis, backend, frontend)
+arty up -d <service>          # Preferred way to manage containers in this project
+```
+
+Production images are built and pushed to `dev.pivoine.art` via Gitea Actions on push to `main`.