chore(spec): sync generated client from upstream openapi.yaml

[ai-stack-dev-vp]

Automated nightly spec sync.

• Regenerated src/graphn/_generated/ from https://cp.graphn.ai/openapi.yaml.
• All tests passed against the regenerated client.

Review the diff for any breaking field renames before merging.

[kunwar-vp]

Closing as a duplicate test artifact. This PR was auto-opened by the workflow_dispatch validation run for #13 — the dispatch ref was chore/spec-sync-use-pat, which peter-evans/create-pull-request defaults to as the PR base, so this PR points spec-sync/auto -> chore/spec-sync-use-pat instead of -> main. The real spec-sync PR is #12 (spec-sync/auto -> main, identical content). Real scheduled runs fire from main and won't hit this. Closing without merging.