chore: Address DSL audit comments

[federicobarbacovi]

🧾 Audit Context

Address DSL audit comments.

🛠️ Changes Made

• Fix typos in docs
• Fix broken links (they now point at a fixed commit)
• Simplify deserialisation function
• Fix wrong parameter in QuadConstraintTests
• Change usage of std::visit from if/else with constexpr to overloads. This ensures compiler failure if we forget to handle some cases (as it was: we were not handling Call)

✅ Checklist

• Audited all methods of the relevant module/class
• Audited the interface of the module/class with other (relevant) components
• Documented existing functionality and any changes made (as per Doxygen requirements)
• Resolved and/or closed all issues/TODOs pertaining to the audited files
• Confirmed and documented any security or other issues found (if applicable)
• Verified that tests cover all critical paths (and added tests if necessary)
• Updated audit tracking for the files audited (check the start of each file you audited)

📌 Notes for Reviewers

(Optional) Call out anything that reviewers should pay close attention to — like logic changes, performance implications, or potential regressions.

[federicobarbacovi]

We didn't need the full program, program without brillig was enough (we just need the function). Do you see any problem with this? @ludamad