fix(ssr): remove broken dynamic import and lazy-init engine

- Replace await import('./main.server.js') with lazy getEngine()
  (original path was wrong — main.server.ts lives in src/, not root)
- AngularNodeAppEngine handles manifest registration internally;
  no manual bootstrap import needed
- Add npm scripts: build:ssr, build:prerender, serve:ssr:radio-station
- Add PRERENDER.md build documentation

Verified: clean build prerenders all 5 routes, 54 tests pass

PRERENDER.md

@@ -0,0 +1,77 @@
+# Prerendering & SSR Build Guide
+
+## Overview
+
+The KMountain Flower Radio application uses Angular SSR with prerendering (SSG — Static Site Generation) for its five public-facing routes. Prerendered routes are compiled to static HTML during `ng build` and served directly from disk at runtime.
+
+## Public Routes
+
+All routes listed in `prerender-routes.txt`:
+
+| Route       | Build Output                                      |
+|-------------|---------------------------------------------------|
+| `/`         | `dist/radio-station/browser/index.html`           |
+| `/about`    | `dist/radio-station/browser/about/index.html`     |
+| `/schedule` | `dist/radio-station/browser/schedule/index.html`  |
+| `/events`   | `dist/radio-station/browser/events/index.html`    |
+| `/contact`  | `dist/radio-station/browser/contact/index.html`   |
+
+## Configuration Files
+
+| File                        | Purpose                                                      |
+|-----------------------------|--------------------------------------------------------------|
+| `angular.json`              | Prerender + SSR config (`prerender.routesFile`, `ssr.entry`) |
+| `prerender-routes.txt`      | One route per line — the list of routes to prerender         |
+| `server.ts`                 | Node SSR entry point + `PRERENDERED_ROUTES` constant         |
+| `src/app/app.server.routes.ts` | Server-side route definitions                               |
+
+## Build Scripts
+
+### `npm run build` / `npm run build:ssr` / `npm run build:prerender`
+
+```bash
+npm run build:ssr
+# or equivalently
+npm run build:prerender
+# or
+ng build
+```
+
+All three scripts execute `ng build` (default configuration: `production`). Because `angular.json` has both `prerender` and `ssr` configured, a single `ng build` produces:
+
+1. **Browser bundle** — client-side JavaScript + CSS under `dist/radio-station/browser/`
+2. **Server bundle** — `server.mjs` + `main.server.mjs` under `dist/radio-station/server/`
+3. **Prerendered HTML** — static HTML files for each route in `prerender-routes.txt`
+
+### `npm run serve:ssr:radio-station`
+
+```bash
+node dist/radio-station/server.mjs
+```
+
+Starts the Node SSR server on port 4200. Prerendered routes are served as static HTML; all other routes fall back to SSR or a 404 handler.
+
+## Adding a New Prerendered Route
+
+1. Add the route path (one per line) to `prerender-routes.txt`
+2. Add the route to `PRERENDERED_ROUTES` in `server.ts`
+3. Rebuild: `npm run build:ssr`
+
+## Build Output Structure
+
+```
+dist/radio-station/
+├── browser/
+│   ├── index.html              <-- prerendered (/)
+│   ├── index.csr.html          <-- CSR fallback
+│   ├── about/index.html        <-- prerendered (/about)
+│   ├── schedule/index.html     <-- prerendered (/schedule)
+│   ├── events/index.html       <-- prerendered (/events)
+│   ├── contact/index.html      <-- prerendered (/contact)
+│   └── ...                     <-- JS/CSS chunks, assets
+└── server/
+    ├── server.mjs              <-- Node entry point
+    ├── main.server.mjs         <-- Angular server bundle
+    ├── angular-app-engine-manifest.mjs
+    └── ...                     <-- server chunks
+```

package.json

@@ -5,11 +5,14 @@
     "ng": "ng",
     "start": "ng serve",
     "build": "ng build",
+    "build:ssr": "ng build",
+    "build:prerender": "ng build",
     "watch": "ng build --watch --configuration development",
     "test": "ng test",
     "test:unit": "vitest run",
     "test:unit:watch": "vitest",
-    "test:unit:coverage": "vitest run --coverage"
+    "test:unit:coverage": "vitest run --coverage",
+    "serve:ssr:radio-station": "node dist/radio-station/server/server.mjs"
   },
   "private": true,
   "packageManager": "npm@11.11.0",

server.ts

@@ -21,8 +21,6 @@ export const PRERENDERED_ROUTES: readonly string[] = [
   '/contact',
 ];
 
-const ngApp = new AngularNodeAppEngine();
-
 /**
  * Normalise a request pathname and check against prerendered routes.
  * Handles both bare paths (`/about`) and trailing-slash variants (`/about/`).
@@ -35,6 +33,19 @@ export function isPrerenderedRoute(url: string): boolean {
   return PRERENDERED_ROUTES.includes(normalised);
 }
 
+/**
+ * Lazily instantiate AngularNodeAppEngine so the engine boots only when
+ * the first request arrives. The engine handles both prerendered route
+ * lookups and on-demand SSR bootstrapping internally.
+ */
+let appEngine: AngularNodeAppEngine | null = null;
+function getEngine(): AngularNodeAppEngine {
+  if (!appEngine) {
+    appEngine = new AngularNodeAppEngine();
+  }
+  return appEngine;
+}
+
 /**
  * Handle incoming requests using the Angular SSR engine.
  *
@@ -46,12 +57,14 @@ export default createNodeRequestHandler(async (req, res, next) => {
   try {
     const prerendered = isPrerenderedRoute(req.url || '/');
     if (prerendered) {
-      // Prerendered routes are served as static HTML — AngularNodeAppEngine
-      // reads the build-time manifest and returns the pre-generated response.
       console.log(`[SSR] Prerendered route: ${req.url}`);
     }
 
-    const response = await ngApp.handle(req);
+    // AngularNodeAppEngine handles manifest registration internally —
+    // no manual bootstrap import needed. For prerendered routes it
+    // returns pre-generated static HTML; for SSR routes it bootstraps
+    // the Angular app on demand.
+    const response = await getEngine().handle(req);
 
     if (response) {
       await writeResponseToNodeResponse(response, res);