Adopt unstable_stream API for internal middleware implementation (#14103)

Author: brophdawg11

.changeset/rare-mice-report.md

@@ -0,0 +1,31 @@
+---
+"react-router": patch
+---
+
+[UNSTABLE] Rename and alter the signature/functionality of the `unstable_respond` API in `staticHandler.query`/`staticHandler.queryRoute`
+
+- The API has been renamed to `unstable_generateMiddlewareResponse` for clarity
+- The main functional change is that instead of running the loaders/actions before calling `unstable_respond` and handing you the result, we now pass a `query`/`queryRoute` function as a parameter and you execute the loaders/actions inside your callback, giving you full access to pre-processing and error handling
+- The `query` version of the API now has a signature of `(query: (r: Request) => Promise<StaticHandlerContext | Response>) => Promise<Response>`
+- The `queryRoute` version of the API now has a signature of `(queryRoute: (r: Request) => Promise<Response>) => Promise<Response>`
+- This allows for more advanced usages such as running logic before/after calling `query` and direct error handling of errors thrown from query
+- ⚠️ This is a breaking change if you've adopted the `staticHandler` `unstable_respond` API
+
+```tsx
+let response = await staticHandler.query(request, {
+  requestContext: new unstable_RouterContextProvider(),
+  async unstable_generateMiddlewareResponse(query) {
+    try {
+      // At this point we've run middleware top-down so we need to call the
+      // handlers and generate the Response to bubble back up the middleware
+      let result = await query(request);
+      if (isResponse(result)) {
+        return result; // Redirects, etc.
+      }
+      return await generateHtmlResponse(result);
+    } catch (error: unknown) {
+      return generateErrorResponse(error);
+    }
+  },
+});
+```

.changeset/rare-mice-report2.md

@@ -0,0 +1,5 @@
+---
+"react-router": patch
+---
+
+[UNSTABLE] Convert internal middleware implementations to use the new `unstable_generateMiddlewareResponse` API