fix: adapt frontend for legacy Chrome and runtime config

frontend-web/postcss.config.js

@@ -1,5 +1,11 @@
-export default {
-  plugins: {
-    "@tailwindcss/postcss": {},
-  },
-};
+import tailwindcss from "@tailwindcss/postcss";
+import legacyColorFallback from "./scripts/postcss-legacy-color-fallback.mjs";
+import lightningCssLegacyChrome from "./scripts/postcss-lightningcss-chrome109.mjs";
+
+export default {
+  plugins: [
+    tailwindcss(),
+    legacyColorFallback(),
+    lightningCssLegacyChrome(),
+  ],
+};