Add Dockerfile for application setup, update next.config.ts for standalone output, enhance documentation for FFMPEG_PATH, and implement ffmpeg location flag in download functionality

Dockerfile

@@ -0,0 +1,55 @@
+FROM node:20-alpine AS base
+
+# Install dependencies needed for yt-dlp and ffmpeg
+RUN apk add --no-cache \
+    python3 \
+    ffmpeg \
+    ca-certificates \
+    && wget https://github.com/yt-dlp/yt-dlp/releases/latest/download/yt-dlp -O /usr/local/bin/yt-dlp \
+    && chmod a+rx /usr/local/bin/yt-dlp
+
+# Set environment variables
+ENV YT_DLP_PATH=/usr/local/bin/yt-dlp
+ENV FFMPEG_PATH=/usr/bin/ffmpeg
+
+# Install dependencies only when needed
+FROM base AS deps
+WORKDIR /app
+
+COPY package.json package-lock.json* ./
+RUN npm ci
+
+# Build the application
+FROM base AS builder
+WORKDIR /app
+
+COPY --from=deps /app/node_modules ./node_modules
+COPY . .
+
+RUN npm run build
+
+# Production image
+FROM base AS runner
+WORKDIR /app
+
+ENV NODE_ENV=production
+
+RUN addgroup --system --gid 1001 nodejs
+RUN adduser --system --uid 1001 nextjs
+
+# Create downloads directories
+RUN mkdir -p /app/downloads /app/public/downloads \
+    && chown -R nextjs:nodejs /app
+
+COPY --from=builder /app/public ./public
+COPY --from=builder --chown=nextjs:nodejs /app/.next/standalone ./
+COPY --from=builder --chown=nextjs:nodejs /app/.next/static ./.next/static
+
+USER nextjs
+
+EXPOSE 3000
+
+ENV PORT=3000
+ENV HOSTNAME="0.0.0.0"
+
+CMD ["node", "server.js"]