fix: ensure StaticSite uploads html after other assets

platform/src/components/aws/static-site.ts

@@ -937,7 +937,53 @@ export class StaticSite extends Component implements Link.Linkable {
 
           // Upload files based on fileOptions
           const filesProcessed: string[] = [];
-          for (const fileOption of fileOptions.reverse()) {
+          const reversedFileOptions = [...fileOptions].reverse();
+          const htmlFileOptions: typeof reversedFileOptions = [];
+          const nonHtmlFileOptions: typeof reversedFileOptions = [];
+
+          /**
+           * StaticSite historically replays `fileOptions` in reverse order, so
+           * the *last* entry in config becomes the *first* upload pass. With
+           * the default options that put HTML last, the runtime actually pushes
+           * `index.html` to S3 *before* its hashed JS/CSS siblings:
+           *
+           * ```text
+           * deploy start
+           *   ├─▶ (reverse) upload index.html
+           *   │       └─▶ CloudFront serves fresh HTML referencing app.[hash].js
+           *   └───── lag ──▶ upload app.[hash].js (still missing in S3)
+           *                               ↓
+           *                           viewer request → S3 403 → white screen
+           * ```
+           *
+           * To close that race we bucket options by whether they touch HTML,
+           * process non-HTML first, then HTML. Behavioural invariants remain:
+           *
+           * ```text
+           * configure: [ ...non-html..., ...html... ]
+           * reverse ▶  [ html-group, non-html-group ]
+           * reorder ▶  [ non-html-group, html-group ]
+           * result  ▶  assets uploaded → index.html uploaded → no 403 gap
+           * ```
+           */
+          for (const option of reversedFileOptions) {
+            const patterns = Array.isArray(option.files)
+              ? option.files
+              : [option.files];
+            const targetsHtml = patterns.some((pattern) =>
+              pattern.includes(".html"),
+            );
+
+            if (targetsHtml) {
+              htmlFileOptions.push(option);
+            } else {
+              nonHtmlFileOptions.push(option);
+            }
+          }
+
+          const uploadOrder = [...nonHtmlFileOptions, ...htmlFileOptions];
+
+          for (const fileOption of uploadOrder) {
             const files = globSync(fileOption.files, {
               cwd: path.resolve(outputPath),
               nodir: true,