release: 0.3.4 (#235)

## Bump
- [ ] Major
- [ ] Minor
- [x] Patch
- [ ] Skip

## Changelog

### Fixed
- RuleSet publish fails when `shacl_rules.external_id` includes a `.ttl` filename suffix — normalize to a valid RuleSet API ID before publishing (#235).
- RuleSet/DataProduct create treats HTTP 400 duplicate responses as already-exists (API returns 400, not 409, when the external ID exists) (#235).

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