feat: Add API-key installation support to Pipes

[gjtorikian]

Summary

• Regenerate the Pipes module from the latest OpenAPI spec (oagen).
• Add updateDataIntegrationApiKey() — upserts an API-key installation for an integration/user via PUT /data-integrations/{slug}/api-key, rotating the stored key if one already exists.
• Add createDataIntegrationCredential() — vends credentials for a connected account via POST /data-integrations/{slug}/credentials, branching on the installation's auth_method (OAuth returns a refreshed access token; API-key returns the stored secret).
• Surface auth_method on connected accounts and provider list entries, with supporting credential/error interfaces and serializers.
• Simplify getAccessToken() to take GetAccessTokenOptions directly (rename get-access-token.interface → get-access-token-options.interface) and document the new 422 response.
• Regenerate fixtures and update pipes.spec.ts to cover the new endpoints.

Test plan

• npm test -- src/pipes/pipes.spec.ts passes
• npm run build / typecheck succeeds with the regenerated interfaces
• Spot-check that no hand-maintained Pipes code was clobbered by regen