MicroProfile mirror-node leaks a JAX-RS Client per request and swallows non-404 errors

### Description

`MirrorNodeRestClientImpl.doGetCall` and every `RestBasedPage` constructor call `ClientBuilder.newClient()` on each request and never close the returned `jakarta.ws.rs.client.Client`. Each `Client` carries an internal thread/connection pool, so under any non-trivial load the process accumulates them until resources are exhausted. The `MirrorNodeClient` CDI producer is `@ApplicationScoped`, so a single shared `Client` is all that is needed.

On top of that, only HTTP 404 is handled: any other 4xx/5xx response is passed straight to `readEntity(JsonObject.class)`, so the caller either gets the mirror-node error payload as if it were valid data or a `ProcessingException` with no status context. `MirrorNodeRestClient.doGetCall` declares `throws HieroException` but never actually throws it for server errors. The Spring module does not have either problem.

`Response` objects are never closed either (try-with-resources would be enough).

### Evidence

- `hiero-enterprise-microprofile/src/main/java/org/hiero/microprofile/implementation/MirrorNodeRestClientImpl.java` (lines 21-29)
- `hiero-enterprise-microprofile/src/main/java/org/hiero/microprofile/implementation/RestBasedPage.java` (lines 49-57) — invoked per page in `next()` and `first()`
- [`jakarta.ws.rs.client.Client` Javadoc](https://jakarta.ee/specifications/restful-ws/4.0/apidocs/jakarta.ws.rs/jakarta/ws/rs/client/client): *"Clients are heavy-weight objects that manage the client-side communication infrastructure. Initialization as well as disposal of a Client instance may be a rather expensive operation."*

### Expected behavior

- `MirrorNodeRestClientImpl` caches a single `Client` + root `WebTarget`, implements `AutoCloseable`, and is disposed via CDI `@Disposes` on the `@ApplicationScoped` producer.
- `RestBasedPage` reuses that `WebTarget` instead of building its own `Client`.
- Non-404 4xx/5xx responses throw `HieroException` with status + path in the message.
- `Response` objects closed deterministically.