Add Docker support and improve Dockerfile configuration

- Added `DOCKER.md` documentation to guide users on using Docker with the project.
- Migrated Dockerfile to use `oven/bun:1-alpine` for performance improvements.
- Refined build process and permissions in the container for better compatibility.
- Excluded `.idea/` files in `.gitignore`.
- Enhanced `.npmignore` to clean redundant blank lines.

Dockerfile

@@ -1,14 +1,20 @@
-FROM node:20-alpine AS builder
+# syntax=docker/dockerfile:1.7
+FROM oven/bun:1-alpine AS base
 WORKDIR /app
 
-COPY package*.json ./
-RUN if [ -f package-lock.json ]; then npm ci --no-audit --no-fund; else npm install --no-audit --no-fund; fi
+FROM base AS builder
+
+RUN apk add --no-cache nodejs npm python3 make g++ linux-headers
+
+COPY package.json ./
+RUN --mount=type=cache,target=/root/.npm \
+  npm install
 
 COPY . ./
 ENV NEXT_TELEMETRY_DISABLED=1
-RUN npm run build
+RUN bun run build:bun
 
-FROM node:20-alpine AS runner
+FROM oven/bun:1-alpine AS runner
 WORKDIR /app
 
 LABEL org.opencontainers.image.title="9router"
@@ -27,13 +33,14 @@ COPY --from=builder /app/src/mitm ./src/mitm
 # Standalone node_modules may omit deps only required by the MITM child process.
 COPY --from=builder /app/node_modules/node-forge ./node_modules/node-forge
 
-RUN mkdir -p /app/data
+RUN mkdir -p /app/data && chown -R bun:bun /app
 
 # Fix permissions at runtime (handles mounted volumes)
-RUN printf '#!/bin/sh\nchown -R node:node /app/data 2>/dev/null; exec su-exec node "$@"\n' > /entrypoint.sh && chmod +x /entrypoint.sh
-RUN apk add --no-cache su-exec
+RUN apk add --no-cache su-exec && \
+  printf '#!/bin/sh\nchown -R bun:bun /app/data 2>/dev/null\nexec su-exec bun "$@"\n' > /entrypoint.sh && \
+  chmod +x /entrypoint.sh
 
 EXPOSE 20128
 
 ENTRYPOINT ["/entrypoint.sh"]
-CMD ["node", "server.js"]
+CMD ["bun", "server.js"]