Convert htmx-redirect-toast.js to TS; remove dead legacy utils.js (issue #17)

- Add ts/htmx-redirect-toast.ts: typed port of the hx-redirect-toast htmx
  extension. Stays a classic (non-module) script — only touches the global
  htmx and registers an extension; layout.py now serves dist/htmx-redirect-toast.js
- Delete games/static/js/utils.js: the legacy hand-written copy is dead — every
  compiled module imports dist/utils.js (from ts/utils.ts); nothing references
  the old path

With this, the only first-party JS served is compiled from ts/; the sole
remaining hand-written .js in static is the vendored datepicker.umd.js bundle.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

ts/htmx-redirect-toast.ts

@@ -0,0 +1,60 @@
+/**
+ * htmx "hx-redirect-toast" extension.
+ *
+ * A custom swap style that performs no DOM swap. On an HX-Redirect response it
+ * navigates immediately (the toast shows on the destination page); otherwise it
+ * turns the HX-Trigger header into CustomEvents so toasts fire in place.
+ *
+ * Classic (non-module) script: it only touches the global htmx and registers an
+ * extension, so it stays a plain <script> like the other vendored-adjacent glue.
+ */
+declare const htmx: any;
+
+(() => {
+  htmx.defineExtension("hx-redirect-toast", {
+    isInlineSwap(swapStyle: string): boolean {
+      return swapStyle === "hx-redirect-toast";
+    },
+    handleSwap(
+      swapStyle: string,
+      target: HTMLElement,
+      fragment: Node,
+      settleInfo: unknown,
+      htmxConfig: { xhr: XMLHttpRequest }
+    ): null {
+      const xhr = htmxConfig.xhr;
+      const hxRedirect = xhr.getResponseHeader("HX-Redirect");
+      const hxTrigger = xhr.getResponseHeader("HX-Trigger");
+
+      // Redirect immediately (toast will be shown on the new page)
+      if (hxRedirect) {
+        window.location.href = hxRedirect;
+      }
+
+      // Only dispatch HX-Trigger events for toasts when not redirecting
+      if (!hxRedirect && hxTrigger) {
+        const triggers = JSON.parse(hxTrigger);
+        const events = Array.isArray(triggers) ? triggers : [triggers];
+        events.forEach((triggerObject: Record<string, unknown>) => {
+          Object.entries(triggerObject).forEach(([name, rawDetail]) => {
+            let detail: unknown = rawDetail;
+            try {
+              detail = JSON.parse(rawDetail as string);
+            } catch {
+              // keep as-is
+            }
+            target.dispatchEvent(
+              new CustomEvent(name, {
+                detail,
+                bubbles: true,
+                cancelable: true,
+              })
+            );
+          });
+        });
+      }
+      // Return null to prevent any DOM swap
+      return null;
+    },
+  });
+})();