Internal: the app session of the workload replays only app code #85

Problem

• The GLMakie extension replays a whole session in the app layout at every precompilation, also the steps whose code the compact session already compiled
• Once the window code is compiled once for both layouts (Internal: window code is compiled once per layout #79), most of these steps compile nothing new but still cost their replay time (two such sessions took about 1.5 min, Internal: precompile workload replays two sessions for nothing #78)

Tasks

• The app session of the workload keeps only steps that compile code of the app layout: object tree, inspector, dock, splitters, toolbar
• The first actions of the app layout compile no more than before, measured per step with benchmark/jit_probe.jl
• The extension precompiles faster than after Internal: window code is compiled once per layout #79, measured the same way

Notes

• Follows Internal: window code is compiled once per layout #79; measure only after it is merged
• Baseline before Internal: window code is compiled once per layout #79: the extension precompiles in 238 s (Windows, Julia 1.13.0, commit 54c179f)