DOC-04: Regenerate and validate OpenAPI spec artifact after Swashbuckle 10 upgrade

[Chris0Jeky]

Context

Swashbuckle.AspNetCore was upgraded from 6.9.0 to 10.1.7 in PR #598. The migration is functionally clean (no deprecated APIs, modern OpenApi types used throughout), but:

1. The exported OpenAPI artifact at artifacts/openapi/taskdeck-api.json was last generated 2025-02-24 — it predates the Swashbuckle upgrade and the 7 new controller OpenAPI annotations added in PR DOC-03: Developer portal generation from OpenAPI and integration examples #605.
2. The exported spec may not reflect the configured API title ("Taskdeck API") or JWT Bearer security scheme — investigation found potential gaps between SwaggerDoc() config and the exported artifact.

Proposal

1. Re-run the OpenAPI export script (scripts/export-openapi-spec.sh or scripts/generate-openapi-artifact.ps1) against the current API
2. Validate the regenerated spec includes: correct title/description, JWT security scheme in components.securitySchemes, all annotated controller endpoints, XML doc comments
3. Commit the refreshed artifact
4. Consider adding the developer portal CI workflow (reusable-developer-portal.yml) to ci-extended so spec drift is caught on PRs that modify controllers

Acceptance Criteria

• artifacts/openapi/taskdeck-api.json regenerated from current API
• Spec validated for title, security scheme, and endpoint completeness
• Developer portal workflow considered for ci-extended integration