feat(site): add webpush notification serviceworker (#17123)

* Improves tests for webpush notifications
* Sets subscriber correctly in web push payload (without this,
notifications do not work in Safari)
* NOTE: for now, I'm using the Coder Access URL. Some push messaging
service don't like it when you use a non-HTTPS URL, so dropping a warn
log about this.
* Adds a service worker and context for push notifications
* Adds a button beside "Inbox" to enable / disable push notifications

Notes:
* ✅ Tested in in Firefox and Safari, and Chrome.

site/vite.config.mts

@@ -1,5 +1,6 @@
 import * as path from "node:path";
 import react from "@vitejs/plugin-react";
+import { buildSync } from "esbuild";
 import { visualizer } from "rollup-plugin-visualizer";
 import { type PluginOption, defineConfig } from "vite";
 import checker from "vite-plugin-checker";
@@ -28,6 +29,19 @@ export default defineConfig({
 		emptyOutDir: false,
 		// 'hidden' works like true except that the corresponding sourcemap comments in the bundled files are suppressed
 		sourcemap: "hidden",
+		rollupOptions: {
+			input: {
+				index: path.resolve(__dirname, "./index.html"),
+				serviceWorker: path.resolve(__dirname, "./src/serviceWorker.ts"),
+			},
+			output: {
+				entryFileNames: (chunkInfo) => {
+					return chunkInfo.name === "serviceWorker"
+						? "[name].js"
+						: "assets/[name]-[hash].js";
+				},
+			},
+		},
 	},
 	define: {
 		"process.env": {
@@ -89,6 +103,10 @@ export default defineConfig({
 				target: process.env.CODER_HOST || "http://localhost:3000",
 				secure: process.env.NODE_ENV === "production",
 			},
+			"/serviceWorker.js": {
+				target: process.env.CODER_HOST || "http://localhost:3000",
+				secure: process.env.NODE_ENV === "production",
+			},
 		},
 		allowedHosts: true,
 	},