feat: v1.1.0 - Swagger docs, mappings, Docker, premium landing page

- Swagger UI interactive docs at /docs
- OpenAPI 3.0 spec at /openapi.json
- mappings field in episodes response (anilistId, malId, kitsuId)
- Docker support (Dockerfile + .dockerignore)
- Premium landing page with try-it buttons (Walter-style)
- Health endpoint with providers list and endpoint count

Dockerfile

@@ -0,0 +1,12 @@
+FROM node:20-alpine
+
+WORKDIR /app
+
+COPY package*.json ./
+RUN npm install --production
+
+COPY . .
+
+EXPOSE 3000
+
+CMD ["node", "server.js"]