feat(01-01): Next.js 15 project with Docker Compose dev environment

- Next.js 15 with App Router, TypeScript, Tailwind CSS (v4), ESLint
- docker-compose.yml with PostgreSQL 16, Redis 7, and app service
- Dockerfile (Node 20 alpine) for containerized development
- .env and .env.example with DATABASE_URL, DATABASE_URL_LOCAL, REDIS_URL
- src/app/page.tsx updated to render NetForge heading
- All three services start healthy with docker compose up -d

.env

@@ -0,0 +1,24 @@
+# =============================================================================
+# NetForge Local Development Environment
+# =============================================================================
+# This file is for local development only. Do NOT commit to version control.
+
+# DATABASE_URL is used by the app inside Docker (app -> db service)
+DATABASE_URL=postgresql://netforge:netforge_dev@db:5432/netforge_dev
+
+# DATABASE_URL_LOCAL is used when running Prisma CLI from host machine
+# e.g., npx prisma db push, npx prisma studio, npx prisma generate
+DATABASE_URL_LOCAL=postgresql://netforge:netforge_dev@localhost:5432/netforge_dev
+
+# Redis (inside Docker)
+REDIS_URL=redis://redis:6379
+
+# Redis (from host)
+REDIS_URL_LOCAL=redis://localhost:6379
+
+# Auth
+NEXTAUTH_SECRET=dev-secret-change-in-production
+NEXTAUTH_URL=http://localhost:3000
+
+# App
+NODE_ENV=development