New Standard "DCM: Capacity Group Collaboration Contact List Data Exchange"

### Description
**As a DCM User,
**I want to share who I am and see who is on "the other side",
**so that I can collaborate easily and have other benefits like in app functionalities (sorting, filtering, dashboards, data analytics, workload management etc.).
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### Acceptance Criteria

- a combined, shared contact list for both supplier and costumer is available
- an active opt-in and opt-out concept is enabled
- data privacy needs are adressed
- easy implementation is enabled in order to have quick and effective market access
- interoperability is considered and ensured in the solution

### Additional Information
DCM Product Vision Alignment (“Collaborative Demand and Capacity Management”)
DCM’s process explicitly includes “Review and Collaborate with Supply Chain Partner” and defines comments as the standardized collaboration mechanism.\ However, comments are text only and do not standardize who the responsible parties are per capacity group.\ The proposed Contact List extension provides a minimal interoperable layer that makes collaboration operational: the “collaborative element” becomes actionable by identifying responsible persons on both sides within the same DCM object context (capacityGroupId).
Why a separate standard (and why reference CX 0014)
• CX 0128 focuses on supply chain planning objects and text collaboration; it does not define structured person/team lists.
• CX 0014 defines identity binding of employees/technical users to companies and requires company BPN attributes in tokens, enabling policy enforcement but not defining object level team semantics.\ Therefore, the Contact List must be a separate semantic model/API (to achieve interoperability) while referencing CX 0014 for the identity foundation.