 with nonexistent version in URL pipe notation silently succeeds (dev only)

## Bug

Same as Issue 18 but using canonical URL pipe notation (`url|version`). The bogus version is silently ignored.

## Repro

```bash
curl -s -o /dev/null -w '%{http_code}' \
  'https://tx-dev.fhir.org/r4/ValueSet/$expand?url=http://hl7.org/fhir/ValueSet/administrative-gender%7C99.0&count=2' \
  -H 'Accept: application/fhir+json'
# Returns: 200 (should be 404/422)
```