docs: add local orbstack setup

compose.yaml

@@ -0,0 +1,45 @@
+services:
+  db:
+    image: postgres:16-alpine
+    container_name: arkie-library-db
+    environment:
+      POSTGRES_USER: ark
+      POSTGRES_PASSWORD: ark
+      POSTGRES_DB: arkdb
+    ports:
+      # Host port 5433 avoids conflicts with any existing local PostgreSQL on 5432.
+      - "5433:5432"
+    volumes:
+      - arkie_postgres_data:/var/lib/postgresql/data
+      - ./migrations/001_init.sql:/docker-entrypoint-initdb.d/001_init.sql:ro
+      - ./migrations/002_wallet_auth.sql:/docker-entrypoint-initdb.d/002_wallet_auth.sql:ro
+    healthcheck:
+      test: ["CMD-SHELL", "pg_isready -U ark -d arkdb"]
+      interval: 5s
+      timeout: 5s
+      retries: 10
+
+  api:
+    build: .
+    container_name: arkie-library-api
+    depends_on:
+      db:
+        condition: service_healthy
+    environment:
+      HTTP_ADDR: ":8080"
+      DATABASE_URL: "postgres://ark:ark@db:5432/arkdb?sslmode=disable"
+      JWT_SECRET: "local-dev-change-me"
+      CORS_ORIGINS: "${CORS_ORIGINS:-http://localhost:5173,http://localhost:3000}"
+      UPLOAD_DIR: "/app/uploads"
+      SEED_ADMIN: "${SEED_ADMIN:-true}"
+      ADMIN_EMAIL: "${ADMIN_EMAIL:-admin@ark.local}"
+      ADMIN_PASSWORD: "${ADMIN_PASSWORD:-admin123}"
+      RUN_WALLET_AUTH_SCHEMA: "true"
+    ports:
+      - "8080:8080"
+    volumes:
+      - arkie_uploads:/app/uploads
+
+volumes:
+  arkie_postgres_data:
+  arkie_uploads: