Regenerate client with openapi-python-client 0.29.0

Pulls in the pending dependabot bumps (openapi-python-client 0.29.0,
ruff 0.15.18, ty 0.0.50, pytest 9.1.0, pytest-asyncio 1.4.0,
actions/checkout 6.0.3, ruff-pre-commit v0.15.15) and regenerates the
client against them.

- 0.29.0 parses timestamps via stdlib datetime.fromisoformat instead of
  dateutil.parser.isoparse, so drop the now-unused python-dateutil runtime
  dependency.
- 0.29.0 emits bare 'return value' (not cast(Enum, value)) in the generated
  enum check_* helpers, which ty 0.0.50 flags as invalid-return-type since
  it can't narrow str to the Literal through the 'value in <set>' guard.
  Ignore that rule for ionq_core/models/** (the only place those helpers
  live; api/** return types stay checked), mirroring the existing
  invalid-argument-type override for generated code.

Author: splch

CHANGELOG.md

@@ -18,11 +18,13 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 ### Changed
 
 - `NativeCircuitInput.qubits` and `JsonMultiCircuitInput.qubits` are now `int | Unset` (previously `float | Unset`), matching upstream's tightening to `format: int32, minimum: 1`. `QisCircuitInput.qubits` already had this type locally via the OpenAPI overlay; that overlay action has been removed now that upstream is correct natively.
+- Regenerated with `openapi-python-client` 0.29.0. Generated models now parse timestamps with the standard library (`datetime.fromisoformat`) instead of `dateutil.parser.isoparse`.
 
 ### Removed
 
 - `get_compiled_file` endpoint (`GET /jobs/{UUID}/circuits/{lang}`) and its `GetCompiledFileLang` enum, removed upstream in favor of `get_job_artifact`. Compiled circuits are now fetched as artifacts by id rather than by `lang` (`"native"` / `"qasm3"`).
 - `CostModel` model, replaced by `ApiCostModel`.
+- The `python-dateutil` runtime dependency, no longer needed now that generated code uses `datetime.fromisoformat`.
 
 ## [0.1.1] - 2026-04-30