Remove dead build-in-production.sh (anchor fork artifact)

This file was a leftover from the anchor/mailship fork. Its function
(removing pnpm overrides, building) is already handled by the Dockerfile
via remove-pnpm-overrides.js. The --no-frozen-lockfile workaround is a
Render CI quirk irrelevant to Docker builds.

Zero references anywhere in the codebase — confirmed via grep.

build-in-production.sh

@@ -1,10 +0,0 @@
-#!/usr/bin/env bash
-
-# Remove link overrides
-node remove-pnpm-overrides.js package.json
-
-# When CI=true as it is on render.com, removing link overrides breaks the lockfile
-pnpm i --no-frozen-lockfile
-
-# Build everything
-pnpm run build