fix: cap V8 heap and enable effective garbage collection for nextjs

Add --max-old-space-size=1024 to the node process running the Next.js
server. This caps V8's old-generation heap at 1024MB, forcing the
garbage collector to run more aggressively as memory usage approaches
the limit.

Previously, users saw Next.js RSS grow to 4GB+. This was caused by a
reference chain that prevented GC from freeing memory:

  AfterContext (vercel/next.js#89091) retained ServerResponse objects
  after client disconnect, which held zlib Transform streams (from
  compress: true), which allocated native C++ buffers outside V8's
  heap entirely — invisible to GC and uncapped by --max-old-space-size.

Combined with the prior commit's fixes (compress: false moves gzip to
nginx, httpBatchLink closes connections faster, socket-cleanup.cjs
destroys zombie CLOSE_WAIT sockets every 60s), GC can now actually
reclaim memory because:

- zlib native buffers no longer exist (compress: false)
- The AfterContext → ServerResponse reference chain is broken by
  socket cleanup destroying the underlying sockets
- The JS heap is capped at 1024MB so V8 GCs more frequently for
  the memory it does control

Also fixes the Dockerfile to copy socket-cleanup.cjs from the builder
stage instead of the host context.

Ref: https://github.com/homarr-labs/homarr/issues/3759

scripts/run.sh

@@ -51,7 +51,7 @@ TASKS_PID=$!
 node apps/websocket/wssServer.cjs &
 WSS_PID=$!
 
-node --require apps/nextjs/socket-cleanup.cjs apps/nextjs/server.js &
+node --max-old-space-size=1024 --require apps/nextjs/socket-cleanup.cjs apps/nextjs/server.js &
 NEXTJS_PID=$!
 
 # Function to handle SIGTERM and shut down services