Add automated check for duplicate Business Capabilities and auto-update list

[andreyyudin]

We need an automated process to keep the UKHSA Business Capability list accurate and up to date.

Currently, this list is used by other validation rules (e.g. ensuring APIs declare their leading business capability). To maintain consistency and avoid downstream validation failures, we should introduce a check to detect and prevent duplicates in the capability list whenever it is updated.

Acceptance Criteria

• A validation step must run on every PR request to make sure that we always have the latest Business Capabilities list.
• If duplicate capabilities are found, the process should fail with a clear error message.
• If no duplicates are found, the list should be automatically updated/merged.
• The check should be integrated into the CI/CD workflow (e.g., PR pipeline).

Example Error Message

• Duplicate capability entry found in Business Capability list: '<capabilityName>'

Notes

• This ensures the list remains the single source of truth.
• It prevents accidental duplication during manual updates.
• Downstream rules (e.g. Spectral checks for x-leading-capability) will then always use a clean, up-to-date list.