perf(build): make standalone image deterministic

Dockerfile

@@ -12,6 +12,7 @@ RUN --mount=type=cache,target=/root/.bun/install/cache \
 # Stage 2: Build the application
 FROM oven/bun:1.3.14-alpine AS builder
 WORKDIR /app
+ENV NEXT_TELEMETRY_DISABLED=1
 COPY --from=deps /app/node_modules ./node_modules
 COPY . .
 # Build Next.js
@@ -20,18 +21,26 @@ RUN --mount=type=cache,target=/app/.next/cache \
 
 # Stage 3: Production runner
 FROM oven/bun:1.3.14-alpine AS runner
+ARG TARGETARCH
 WORKDIR /app
 ENV NODE_ENV=production
 ENV NEXT_TELEMETRY_DISABLED=1
+ENV HOSTNAME=0.0.0.0
+ENV PORT=3000
 
-# Copy built assets and dependencies from builder stage
+# Copy the standalone server and static assets without the full dependency tree
+COPY --from=builder /app/.next/standalone ./
 COPY --from=builder /app/public ./public
-COPY --from=builder /app/.next ./.next
-COPY --from=builder /app/node_modules ./node_modules
-COPY --from=builder /app/package.json ./package.json
+COPY --from=builder /app/.next/static ./.next/static
+
+# The standalone tracer includes both glibc and musl Sharp packages. Alpine only
+# needs musl, so discard the incompatible duplicate without touching runtime deps.
+RUN rm -rf \
+    "./node_modules/@img/sharp-linux-${TARGETARCH}" \
+    "./node_modules/@img/sharp-libvips-linux-${TARGETARCH}"
 
 EXPOSE 3000
-CMD ["bun", "start"]
+CMD ["bun", "server.js"]
 
 # Stage 4: Scheduled video upload worker
 FROM deps AS video-upload-worker