Increase Reference Links Limit per Proposal in Proposal Discussion Forum

[bosko-m]

Update the Proposal Discussion Forum to allow more than 7 reference links per proposal. The current hard limit of 7 reference links restricts authors from providing sufficient context and sources. Raise or remove this cap to support richer proposals (e.g., research papers, forum threads, videos, GitHub issues).

Acceptance Criteria

• The UI permits adding more than 7 reference links to a proposal.
• Backend/API accepts and stores an expanded number of reference links (no validation error at 7).
• Existing proposals with 7 links remain valid and editable.
• Form validation, display, and editing work correctly with larger link lists.