chore(pos): wire slip-layout.js into receipt/cashup/settings, bump SW cache

public/pos/cashup.html

@@ -244,6 +244,7 @@ button:focus-visible,input:focus-visible,select:focus-visible{outline:0;box-shad
 <script src="pos-config.js"></script>
 <script src="theme.js"></script>
 <script src="letterhead-config.js"></script>
+<script src="slip-layout.js"></script>
 <script src="epos-print.js"></script>
 <script>
 (function(){

public/pos/receipt.html

@@ -336,6 +336,7 @@ input,select{font:inherit;color:inherit}
 
 <script src="pos-config.js"></script>
 <script src="theme.js"></script>
+<script src="slip-layout.js"></script>
 <script src="epos-print.js"></script>
 <script>
 (function(){

public/pos/settings.html

@@ -257,6 +257,7 @@ body{display:flex;flex-direction:column;min-height:100dvh;max-width:480px;margin
 <script src="pos-config.js"></script>
 <script src="theme.js"></script>
 <script src="letterhead-config.js"></script>
+<script src="slip-layout.js"></script>
 <script src="epos-print.js"></script>
 <script>
 'use strict';

public/pos/sw.js

@@ -1,5 +1,5 @@
 // Service worker — cache app shell, network-first for HTML + theme.js, cache-first for other static.
-const CACHE = "pos-v22";
+const CACHE = "pos-v23";
 const APP_SHELL = [
   './',
   './index.html',
@@ -11,6 +11,7 @@ const APP_SHELL = [
   './pos-config.js',
   './pos-app.js',
   './letterhead-config.js',
+  './slip-layout.js',
   './epos-print.js',
   './theme.js',
   './manifest.json',