fix CI build issue

Author: erubboli

app/Dockerfile

@@ -1,4 +1,9 @@
-FROM node:22-alpine AS builder
+# syntax=docker/dockerfile:1
+
+# ── Build stage — runs natively on the CI host (no QEMU) ─────────────────────
+# $BUILDPLATFORM is always the host arch (e.g. linux/amd64).
+# TypeScript/Astro compilation is pure JS so this is safe.
+FROM --platform=$BUILDPLATFORM node:22-alpine AS builder
 
 RUN apk add --no-cache python3 make g++ sqlite-dev
 
@@ -11,16 +16,30 @@ RUN npm ci && npm rebuild better-sqlite3
 COPY . .
 RUN npm run build
 
-# ── Production image ──────────────────────────────────
+# ── Prod deps — still on the BUILD platform, but targeting the right arch ─────
+# npm_config_arch tells node-pre-gyp to download / compile the native addon
+# for the TARGET architecture instead of the host architecture.
+FROM --platform=$BUILDPLATFORM node:22-alpine AS prod-deps
+ARG TARGETARCH
+
+RUN apk add --no-cache python3 make g++ sqlite-dev
+
+WORKDIR /app
+COPY package.json package-lock.json ./
+
+# Map Docker arch names (amd64/arm64) to npm arch names (x64/arm64)
+RUN NPM_ARCH=$([ "$TARGETARCH" = "amd64" ] && echo "x64" || echo "$TARGETARCH") && \
+    npm_config_arch=$NPM_ARCH npm ci --omit=dev
+
+# ── Production image ──────────────────────────────────────────────────────────
 FROM node:22-alpine AS runner
 
 WORKDIR /app
 
-# Copy only what's needed to run
-COPY --from=builder /app/dist ./dist
-COPY --from=builder /app/node_modules ./node_modules
-COPY --from=builder /app/package.json ./package.json
-COPY --from=builder /app/wasm-wrappers ./wasm-wrappers
+COPY --from=builder    /app/dist           ./dist
+COPY --from=builder    /app/wasm-wrappers  ./wasm-wrappers
+COPY --from=builder    /app/package.json   ./package.json
+COPY --from=prod-deps  /app/node_modules   ./node_modules
 
 ENV HOST=0.0.0.0
 ENV PORT=4321