test: skip polygon NLPModels test on Julia 1.10

[adrhill]

The Julia lts (NLPModels) job failed on #330 with:

MethodError: no method matching typemax(::Type{Irrational{:π}})
  [2] _is_typemax(x::Irrational{:π})  @ JuMP variables.jl:146
 [14] polygon(; n)                    @ OptimizationProblems PureJuMP/polygon.jl:21

OptimizationProblems' JuMP model of polygon uses π as a variable bound, and JuMP calls typemax on it. typemax(::Irrational) errors on Julia 1.10 but works on 1.11+. Both jobs resolved the same JuMP (v1.32.0) and OptimizationProblems (v0.9.3), so only the Julia version differs. The error comes from building the JuMP reference model, not from SCT.

This PR:

• skips :polygon in test/nlpmodels.jl on VERSION < v"1.11"
• adds CHANGELOG entries for this PR and the transfer to JuliaDiff (chore: transfer repository to JuliaDiff #330)
• bumps the version to 1.2.4-DEV

🤖 Generated with Claude Code

[adrhill]

The two extra invalidations look unrelated.