Fix the inspector caching problem

* I've noticed that on a new version of the inspector, I have to go to the browser's devtools panel and clear site data then reload the page.
* The assets are hashed and immutable, so caching should be allowed for them
* The index.html file is the problem, because if cached, it will point to old assets, and therefore needs to have caching turned forf
* This PR adds appropriate headers to the index.html and assets that are served.

Author: cliffhall

client/bin/client.js

@@ -9,10 +9,34 @@ const __dirname = dirname(fileURLToPath(import.meta.url));
 const distPath = join(__dirname, "../dist");
 
 const server = http.createServer((request, response) => {
-  return handler(request, response, {
+  const handlerOptions = {
     public: distPath,
     rewrites: [{ source: "/**", destination: "/index.html" }],
-  });
+    headers: [
+      {
+        // Ensure index.html is never cached
+        source: "index.html",
+        headers: [
+          {
+            key: "Cache-Control",
+            value: "no-cache, no-store, max-age=0",
+          },
+        ],
+      },
+      {
+        // Allow long-term caching for hashed assets
+        source: "assets/**",
+        headers: [
+          {
+            key: "Cache-Control",
+            value: "public, max-age=31536000, immutable",
+          },
+        ],
+      },
+    ],
+  };
+
+  return handler(request, response, handlerOptions);
 });
 
 const port = process.env.PORT || 6274;