Reduce shared-server build concurrency and memory pressure

Dockerfile

@@ -15,6 +15,8 @@ COPY . .
 FROM source AS builder
 ARG NEXT_PUBLIC_APP_URL
 ENV NEXT_PUBLIC_APP_URL=$NEXT_PUBLIC_APP_URL NEXT_TELEMETRY_DISABLED=1
+# Build-only resource controls for the shared Coolify VM; not runtime settings.
+ENV NEXT_BUILD_CPUS=2 RAYON_NUM_THREADS=2 UV_THREADPOOL_SIZE=2 MALLOC_ARENA_MAX=2 NODE_OPTIONS=--max-old-space-size=1536
 # Build-only placeholders; never copy production secrets into image layers.
 RUN DATABASE_URL=postgres://build:build@127.0.0.1:5432/build BETTER_AUTH_SECRET=build-only-placeholder-secret-not-for-runtime BETTER_AUTH_URL=$NEXT_PUBLIC_APP_URL bun run --filter @album/web build
 

apps/web/next.config.ts

@@ -2,6 +2,10 @@ import type { NextConfig } from "next";
 
 const nextConfig: NextConfig = {
   output: "standalone",
+  experimental: {
+    cpus: process.env.NEXT_BUILD_CPUS ? Math.max(1, Math.min(2, Number(process.env.NEXT_BUILD_CPUS) || 2)) : 2,
+    memoryBasedWorkersCount: false,
+  },
   poweredByHeader: false,
   images: { qualities: [75, 85] },
   async redirects() {

docs/build-safety.md

@@ -0,0 +1,12 @@
+# Shared-server build safety
+
+- Keep Coolify server concurrent builds at **1** (previously 2).
+- Do not run manual Docker builds on the production VM alongside deployments.
+  Validate locally first; then push once and let the webhook build finish.
+- The Docker builder caps Next page-generation workers and Rayon/libuv pools at
+  two. Node subprocesses have a 1536 MiB old-space ceiling. These are not a hard
+  total-memory limit: Bun, native allocations, and separate processes add overhead.
+- Build controls are restricted to the builder stage; application runtime is
+  unchanged. The final image must pass the Sharp WebP smoke test.
+- If memory pressure remains high, move builds to a separate builder rather than
+  increasing concurrency or running more diagnostic builds on the live VM.