spliit: install missing deepmerge transitive dep before build

Spliit imports deepmerge in src/i18n/request.ts but does not declare it
in package.json; Next.js 16 Turbopack rejects phantom dependencies, so
the build fails with 'Module not found: deepmerge'.

ct/spliit.sh

@@ -49,6 +49,7 @@ function update_script() {
     cd /opt/spliit
     set -a && source /opt/spliit/.env && set +a
     $STD npm install
+    $STD npm install deepmerge
     $STD npm run build
     msg_ok "Built Application"
 

install/spliit-install.sh

@@ -41,6 +41,7 @@ msg_info "Building Application"
 cd /opt/spliit
 set -a && source /opt/spliit/.env && set +a
 $STD npm install
+$STD npm install deepmerge
 $STD npm run build
 msg_ok "Built Application"