Starting the SmolPC 2.0 rebuild

SmolPC 2.0 started here. The original LibreOfficeAI and libre-office-mcp codebases were brought together under a single roof, and the project structure was reshaped to reflect where things are heading — renaming the old “apps” layer to “adapters” to better describe what each piece actually does. Most of the work this fortnight was about getting the foundations right before building on top of them.