feat: simplify Dockerfile and reduce image size

Dockerfile

@@ -1,34 +1,31 @@
-FROM node:20-alpine AS base
+FROM node:18-alpine AS base
+
+FROM base AS builder
+
+ENV OPENAI_API_KEY=""
+ENV GOOGLE_API_KEY=""
+ENV CODE=""
 
 # if you located in China, you can use taobao registry to speed up
 # RUN npm config set registry 'https://registry.npmmirror.com/'
 
 RUN npm install -g pnpm@latest-9
 
-FROM base AS deps
-
 WORKDIR /app
 
 COPY .npmrc package.json pnpm-lock.yaml ./
 
-RUN pnpm install
+RUN pnpm install --frozen-lockfile
 
-FROM base AS builder
-
-ENV OPENAI_API_KEY=""
-ENV GOOGLE_API_KEY=""
-ENV CODE=""
-
-WORKDIR /app
-COPY --from=deps /app/node_modules ./node_modules
 COPY . .
 
 RUN pnpm build
 
 FROM base AS runner
+
 WORKDIR /app
 
-RUN apk add proxychains-ng
+RUN apk add --no-cache proxychains-ng
 
 ENV PROXY_URL=""
 ENV OPENAI_API_KEY=""