First step

Ideally, the GUI should be able to perform the following tasks, typically in separate tabs
- OCP definition
- [ ] load a .jl file containing an ocp definition (and choose the name of the ocp)
- [ ] display the loaded ocp (as source code ?)
- [ ] edit/save a .jl in textfield, internally and/or externally
- solve the problem
- [ ] call to solve with default options
- [ ] show solver iterations and output (in GUI or Julia repl)
- [ ] save solution in a .sol file (add a function in CTDirect ? use native julia save ?)
- [ ] set options for solve, including initial guess options (warmstart in particular)
- [ ] discrete continuation (but how to change the parameter in the ocp ? julia repl may be more handy for that)
- plot the solution
- [ ] basic display of plot command (in GUI or external window)
- [ ] save the graphs
- [ ] load and display a solution file (cf save solution: add CTDirect function or native julia ?)
- [ ] edit / custom graphs
- meta
- [ ] bundle the app, ie without the need to launch from julia repl
- [ ] open a julia repl *inside* the gui

The issue names no source files, tests, or entry points. Start by inspecting the existing GUI structure and Julia integration, then split the requested OCP loading, solving, plotting, packaging, and embedded REPL capabilities into separately scoped tasks with agreed completion criteria.

Written by the indexing model from the issue text.