Integrate Constitution Checker for Parameter Update Proposals in Proposal Discussion Forum

### Description
When creating or submitting a Parameter Update Proposal in the Proposal Discussion Forum pillar, integrate a step that checks the constitutionality of the proposal using the open-source Constitution Checker.

This tool performs validation against the guardrails outlined in the Cardano Constitution.

Reference: https://github.com/input-output-hk/constitution-checker

### Acceptance Criteria
- Constitution Checker is triggered before submission of any Parameter Update Proposal.
- UI provides a clear pass/fail indication with any guardrail violations listed.
- Link to full constitution checker tool or documentation is available.