Scenario Config and VS Code

Scenario and tool configuration are covered by spec/SPEC_0018_TOOL_CONFIG.md.

Rumoca now prefers colocated rum.toml files for runnable scenarios. A rum.toml file uses TOML content, lives next to the example it controls, and describes one task: simulation, code generation, or another explicit tool action.

VS Code should run rum.toml scenarios directly. The play action belongs on the scenario, not on a .mo file that requires guessing the model, source roots, solver, and viewer.

Workspace Modelica paths are editor settings. Keep repo-committable dependency paths in workspace .vscode/settings.json files when that is useful for examples. Scenario-specific paths belong in the rum.toml scenario.