fix: define global toast utility in app-init

- Added window.toast() in app-init.js so workshop/customers/inventory pages can use it.

- Bumped app-init.js cache version on all templates.

pos/static/js/app-init.js

@@ -215,4 +215,21 @@
         });
     }
 
+    // ─── Global toast utility ───
+    window.toast = function(msg, type) {
+        type = type || 'success';
+        var bg = type === 'error' ? '#d32f2f' : '#388e3c';
+        var el = document.createElement('div');
+        el.style.cssText = 'position:fixed;bottom:20px;right:20px;z-index:99999;padding:12px 20px;border-radius:8px;background:' + bg + ';color:#fff;font-weight:500;box-shadow:0 4px 12px rgba(0,0,0,.2);opacity:0;transition:opacity .3s;';
+        el.textContent = msg;
+        document.body.appendChild(el);
+        // trigger reflow
+        el.offsetHeight;
+        el.style.opacity = '1';
+        setTimeout(function() {
+            el.style.opacity = '0';
+            setTimeout(function() { if (el.parentNode) el.parentNode.removeChild(el); }, 300);
+        }, 3000);
+    };
+
 })();