Pure request-building logic ported from web/src/components/spawn/model.ts, plus a testable SpawnViewModel wiring presets, projects, debounced dir autocomplete, branch loading, and session creation to MaestroClient.
Pure request-building logic ported from web/src/components/spawn/model.ts, plus a testable SpawnViewModel wiring presets, projects, debounced dir autocomplete, branch loading, and session creation to MaestroClient.