fix(web): use 50% rather than 75% for the web heap limit

At a 16GiB limit this gives the web process an 8384MiB ceiling (up from
4288MiB), which still resolves the GC thrash while leaving roughly 7.7GiB for
page cache. zoekt currently uses ~5.8GiB of file cache for its EFS-backed
index, and 75% would have squeezed that to ~3.6GiB.

50% also matches Node's own default curve below the ~4GiB cap, so deployments
at or under 8GiB are unaffected by this change.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

Author: brendan-kellam

supervisord.conf

@@ -16,7 +16,7 @@ redirect_stderr=true
 [program:web]
 command=./prefix-output.sh node packages/web/server.js
 # Node's default heap limit caps at ~4GiB regardless of container memory.
-environment=NODE_OPTIONS="--max-old-space-size-percentage=75"
+environment=NODE_OPTIONS="--max-old-space-size-percentage=50"
 priority=20
 autostart=true
 autorestart=true