[Bug] `interpret` errors on models loaded from BMA files

[ReubenJ]

Description

Models loaded from BMA files using the new QN constructor from #38 are not executable because their grammar doesn't match the existing grammar. All operators like max are lowercase in the files and they're uppercase in our grammar. We should switch to lowercase for consistency.

Package Version

0.0.4

Julia Version

1.11.6

Reproduction steps

pkg> activate --temp
pkg> add GraphDynamicalSystems, JSON, DynamicalSystems
julia> using GraphDynamicalSystems, JSON, DynamicalSystems
julia> f = "test/resources/bma_models/well_formed_examples/ToyModelStable.json";
"test/resources/bma_models/well_formed_examples/ToyModelStable.json"
julia> using GraphDynamicalSystems, JSON, DynamicalSystems
julia> step!(create_qn_system(QN(f)), 100)

Relevant log output

Got exception outside of a @test
  Unhandled Expr in `interpret`: max(min(1, min(max(AKT1_136, 0), 1)), 0)
  Stacktrace:
    [1] error(s::String)
      @ Base ./error.jl:35
    [2] interpret(e::Expr, qn::QualitativeNetwork{317, Asynchronous()})
      @ GraphDynamicalSystems ~/Repositories/JuliaProjects/GraphDynamicalSystems.jl/src/qualitative_networks.jl:411
    [3] async_qn_step!(qn::QualitativeNetwork{317, Asynchronous()})
      @ GraphDynamicalSystems ~/Repositories/JuliaProjects/GraphDynamicalSystems.jl/src/qualitative_networks.jl:448
    [4] step!
      @ ~/.julia/packages/DynamicalSystemsBase/kc7rt/src/core_systems/arbitrary_steppable.jl:74 [inlined]
    [5] step!(ds::DynamicalSystemsBase.ArbitrarySteppable{StaticArraysCore.MVector{317, Int64}, QualitativeNetwork{317, Asynchronous()},
 typeof(GraphDynamicalSystems.async_qn_step!), typeof(GraphDynamicalSystems.reset_model!), typeof(GraphDynamicalSystems.extract_state), 
typeof(GraphDynamicalSystems.extract_parameters), MetaGraphsNext.MetaGraph{Int64, Graphs.SimpleGraphs.SimpleDiGraph{Int64}, Symbol, Grap
hDynamicalSystems.Entity{Int64}, Nothing, DataType, MetaGraphsNext.var"#11#13", Float64}, DynamicalSystemsBase.var"#22#24"{typeof(GraphD
ynamicalSystems.reset_model!)}}, n::Int64)
      @ DynamicalSystemsBase ~/.julia/packages/DynamicalSystemsBase/kc7rt/src/core_systems/arbitrary_steppable.jl:73
    [6] top-level scope
      @ ~/Repositories/JuliaProjects/GraphDynamicalSystems.jl/test/qn_test.jl:154

Operating System

Mac