sdlc-vue-state-management

State management decision tree for Vue 3 SPAs: ref/reactive locally, composables for shared logic, Pinia for app-wide state, provide/inject for DI, TanStack Query Vue for server state. Vuex pointer for Vue 2 legacy. Use this skill to: - Pick the right state tool for the data shape (local / shared / server / form). - Implement a Pinia store (Setup syntax preferred). - Use provide/inject correctly with InjectionKey<T>. - Set up TanStack Query Vue for server state. - Migrate from Vuex (with caution; only if BA asks). Do NOT use this skill for: - General SFC conventions (see vue-conventions). - Form state (see vue-forms — vee-validate handles that). - Routing state (see vue-routing — use vue-router useRoute). - Testing stores (see vue-testing).