What problem does it solve? Working on the entangled-manager GUI without breaking its invariants is hard: views must never mutate state, nothing may block the frame loop, child VM processes must survive the manager, and engine/firmware resolution must never ask the user for paths the app can resolve itself. This Skill encodes those architectural rules, form conventions, theme tokens, and WSL backend pitfalls so changes stay consistent. ## Core Features & Use Cases - Architecture guardrails: Documents the Action-based unidirectional data flow (views push intents, only ManagerApp::apply mutates), worker-thread patterns, and child-process supervision rules (own process group, log-file tailing, SIGTERM with 20s grace). - Form and theme conventions: Enforces tooltip-based explanations, single label column via ui::form_scope, native path pickers off the egui thread, and the quantum theme token table in theme.rs. - WSL backend knowledge: Covers engine probing, error translation (execvpe failures, glibc mismatches), digest-pinned engine downloads, and Windows-to-WSL path translation. - Use Case: When adding a new button to a VM card, follow the Skill to add an Action variant, keep the view pure, and verify layout with a --mock --screenshot run. ## Quick Start Load the gui-manager skill before modifying any code in apps/manager, then describe the GUI change you want to make.