Push HMR updates before the SSR rebuild in dev

Client-only edits are sent to the browser right after the hydration build,
without re-running server functions; SSR rebuilds afterwards and props are
re-fetched only when a .server.ts output changed or after fullRebuild. Page
requests wait for an in-flight SSR rebuild. The SSR build no longer runs
Tailwind, the PostCSS processor is reused across rebuilds, and the watcher
debounce drops from 200ms to 50ms.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

dist/functions/server/server-post-build-fn.d.ts

@@ -10,5 +10,14 @@ type Params = {
      */
     changed_pages?: string[];
 };
+/**
+ * # Push a client-only HMR update
+ * Sends the new client bundle to every controller whose page is in
+ * `changed_pages`, without re-running server functions. The payload carries
+ * no `page_props`, so the browser keeps its current props and only swaps the
+ * hydration script/CSS. Used right after the hydration build so the browser
+ * doesn't wait for the SSR rebuild.
+ */
+export declare function pushClientUpdate(changed_pages: string[]): void;
 export default function serverPostBuildFn(params?: Params): Promise<void>;
 export {};