bug: sentry for Astro integration does NOT capture errors on API routes #25729

// sentry.server.config.ts (project root)
import * as Sentry from "@sentry/astro";
Sentry.init({ dsn: process.env.SENTRY_DSN });

// src/pages/api/test-error.ts
import type { APIRoute } from "astro";
export const prerender = false;
export const GET: APIRoute = async () => { throw new Error(`smoke test ${new Date().toISOString()}`); };

### Steps to Reproduce

1. `npm run dev`
2. GET `/api/test-error` twice. Both answer 500.
3. GET `/` once (any `.astro` page).
4. GET `/api/test-error` twice more.

### Expected Result

All four endpoint errors reach Sentry, because `sentry.server.config.ts` runs before the first request of any kind.

### Actual Result

The two errors from step 2 never arrive; with `debug: true` the log shows no `Captured error event` for them. `sentry.server.config.ts` runs during step 3, and the errors from step 4 are captured and delivered. The only difference is that a page module loaded in between.

Cause: the integration loads the server config with `injectScript("page-ssr", …)` (`packages/astro/src/integration/index.ts`). Astro attaches `page-ssr` scripts to `.astro` page modules only, so an endpoint under `src/pages/api/` never imports it. In the production build the config ends up in its own chunk and `dist/server/entry.mjs` reaches it only through a dynamic `import("./chunks/…")` from the page chunks. Until a page renders, `getClient()` is undefined, the request middleware the integration installs takes its `if (!getClient()) return next()` branch, and the uncaught throw is dropped. A deployment that only receives webhooks never initialises Sentry.

### Additional Context

Workaround that I verified on the production build (a freshly started server then delivers endpoint errors with no page render):

```ts
// src/middleware.ts
import "../sentry.server.config";
import { defineMiddleware } from "astro:middleware";
export const onRequest = defineMiddleware((_ctx, next) => next());