React 19 modernization: forwardRef removal, Compiler, ErrorBoundary, Suspense, native <script>

Adopt React 19 idioms across the codebase. The runtime was already on
react@19.2.5 but no React 19 APIs were in use.

- forwardRef -> ref-as-prop in 7 layout/component files
  (NitroInput/Button/ItemCountBadge/Card×5/InfiniteGridItem,
  ToolbarItemView, AvatarEditorIcon)
- <Ctx.Provider> -> <Ctx> in 6 contexts (CatalogAdmin, FloorplanEditor,
  UiSettings, GridContext, NitroCardContext, NitroCardAccordionContext)
- Native <script> hoisting for Turnstile, ExternalPluginLoader, GoogleAdsView
  (React 19 dedupes by src; removes manual document.head.appendChild +
  module-level promise caches)
- React Compiler enabled at build time via babel-plugin-react-compiler
  in vite.config.mjs (target: '19'), plus eslint-plugin-react-compiler
  in lint mode
- Global <ErrorBoundary> + <Suspense> in src/index.tsx using
  react-error-boundary, with LoadingView as fallback
- BackgroundsView migrated to use(promise) as a demonstrator pattern
  for Suspense-driven config loading
- ESLint react setting bumped 18.3.1 -> 19.2; legacy
  @typescript-eslint/ban-types replaced with no-restricted-types
  (the old rule was removed in @typescript-eslint v8)
- Refresh public/configuration/{asset-loader,bootstrap}.js to match
  current write-asset-loader.mjs output

Phase 3 (login forms -> useActionState/useFormStatus) deferred:
LoginView is 1623 lines with lockout + Turnstile + heartbeat
interleaving; safer as its own PR.

https://claude.ai/code/session_01GrR87LAqnAEyKG2ZbmQt5Q

public/configuration/asset-loader.js

@@ -44,6 +44,11 @@
     return new URL(".", source);
   };
 
+  const getDeployBase = () => {
+    try { return new URL("..", getBase()); }
+    catch { return new URL("/", location.href); }
+  };
+
   const withCacheBust = (url) => {
     url.searchParams.set("v", Date.now().toString(36));
     return url;
@@ -71,9 +76,14 @@
 
   const resolveAssetCandidates = (path) => {
     const base = getBase();
+    const deploy = getDeployBase();
     const normalized = path.replace(/^\.\//, "");
     const file = normalized.split("/").pop();
+    const relative = normalized.replace(/^\//, "");
     const urls = [
+      new URL("src/assets/" + file, deploy),
+      new URL("assets/" + file, deploy),
+      new URL(relative, deploy),
       new URL("./src/assets/" + file, base),
       new URL("./assets/" + file, base),
       new URL("/src/assets/" + file, base.origin),
@@ -205,7 +215,10 @@
 
   const fetchManifest = async () => {
     const base = getBase();
+    const deploy = getDeployBase();
     const candidates = [
+      new URL(".vite/manifest.json", deploy),
+      new URL("manifest.json", deploy),
       new URL(".vite/manifest.json", base.origin + "/"),
       new URL("manifest.json", base.origin + "/"),
       new URL(".vite/manifest.json", base),
@@ -221,7 +234,11 @@
         const json = await response.json();
         if(json && typeof json === "object") {
           debug("loader: manifest from " + candidate.href);
-          return { manifest: json, base: new URL(".", candidate.href) };
+          let manifestBase = new URL(".", candidate.href);
+          if(/\/\.vite\/manifest\.json$/.test(candidate.pathname)) {
+            manifestBase = new URL("..", manifestBase);
+          }
+          return { manifest: json, base: manifestBase };
         }
       } catch {}
     }
@@ -247,18 +264,24 @@
   const resolveManifestPath = (manifestBase, file) => {
     if(/^https?:\/\//i.test(file)) return file;
     if(file.startsWith("/")) return file;
-    return new URL(file, manifestBase.origin + "/").pathname;
+    return new URL(file, manifestBase).pathname;
   };
 
   const isLoaderUrl = (href) => /(?:^|\/)bootstrap\.js(?:$|\?|#)/i.test(href) || /(?:^|\/)asset-loader\.js(?:$|\?|#)/i.test(href);
 
   const fetchEntryFromIndexHtml = async () => {
     const base = getBase();
+    const deploy = getDeployBase();
     const candidates = [
+      new URL("index.html", deploy),
+      new URL("./", deploy),
       new URL("/index.html", base.origin + "/"),
       new URL("/", base.origin + "/")
     ];
+    const seen = new Set();
     for(const candidate of candidates) {
+      if(seen.has(candidate.href)) continue;
+      seen.add(candidate.href);
       try {
         const response = await fetch(withCacheBust(new URL(candidate.href)), { cache: "no-store" });
         if(!response.ok) continue;