perf(docker): prune runtime before copy

Dockerfile

@@ -10,18 +10,22 @@ RUN --mount=type=cache,target=/root/.bun/install/cache \
     bun install --frozen-lockfile
 
 # Stage 2: Build the application
-FROM oven/bun:1.3.14-alpine AS builder
-WORKDIR /app
+FROM deps AS builder
+ARG TARGETARCH
 ENV NEXT_TELEMETRY_DISABLED=1
-COPY --from=deps /app/node_modules ./node_modules
 COPY . .
 # Build Next.js
 RUN --mount=type=cache,target=/app/.next/cache \
     bun run build
 
+# The standalone tracer includes both glibc and musl Sharp packages. Alpine only
+# needs musl, so prune the incompatible copy before it enters a runtime layer.
+RUN rm -rf \
+    ".next/standalone/node_modules/@img/sharp-linux-${TARGETARCH}" \
+    ".next/standalone/node_modules/@img/sharp-libvips-linux-${TARGETARCH}"
+
 # 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
@@ -33,12 +37,6 @@ COPY --from=builder /app/.next/standalone ./
 COPY --from=builder /app/public ./public
 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", "server.js"]