Fix arm64 Docker build crash (QEMU illegal instruction); v1.1.13

Run npm ci on the native build platform using --platform=\$BUILDPLATFORM in a
deps stage, then copy node_modules to the runtime image. Avoids running Node.js
under QEMU emulation, which crashes with SIGILL on arm64 cross-builds.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Dockerfile

@@ -1,3 +1,10 @@
+# Install prod deps on the native builder platform to avoid QEMU npm crashes
+# during cross-platform builds. All deps are pure-JS so this is safe.
+FROM --platform=$BUILDPLATFORM node:22-alpine AS deps
+WORKDIR /app
+COPY package*.json ./
+RUN npm ci --omit=dev --legacy-peer-deps
+
 FROM node:22-alpine AS runtime
 WORKDIR /app
 
@@ -7,8 +14,7 @@ ENV PORT=4173
 ARG COMMIT_SHA=unknown
 ENV COMMIT_SHA=${COMMIT_SHA}
 
-COPY package*.json ./
-RUN npm ci --omit=dev --legacy-peer-deps
+COPY --from=deps /app/node_modules ./node_modules
 
 COPY dist ./dist
 COPY server.js ./server.js