chore: import upstream snapshot with attribution

.claude/rules/sim-stores.md

@@ -0,0 +1,71 @@
+---
+paths:
+  - "apps/sim/**/store.ts"
+  - "apps/sim/**/stores/**/*.ts"
+---
+
+# Zustand Store Patterns
+
+Stores live in `stores/`. Complex stores split into `store.ts` + `types.ts`.
+
+## Basic Store
+
+```typescript
+import { create } from 'zustand'
+import { devtools } from 'zustand/middleware'
+import type { FeatureState } from '@/stores/feature/types'
+
+const initialState = { items: [] as Item[], activeId: null as string | null }
+
+export const useFeatureStore = create<FeatureState>()(
+  devtools(
+    (set, get) => ({
+      ...initialState,
+      setItems: (items) => set({ items }),
+      addItem: (item) => set((state) => ({ items: [...state.items, item] })),
+      reset: () => set(initialState),
+    }),
+    { name: 'feature-store' }
+  )
+)
+```
+
+## Persisted Store
+
+```typescript
+import { create } from 'zustand'
+import { persist } from 'zustand/middleware'
+
+export const useFeatureStore = create<FeatureState>()(
+  persist(
+    (set) => ({
+      width: 300,
+      setWidth: (width) => set({ width }),
+      _hasHydrated: false,
+      setHasHydrated: (v) => set({ _hasHydrated: v }),
+    }),
+    {
+      name: 'feature-state',
+      partialize: (state) => ({ width: state.width }),
+      onRehydrateStorage: () => (state) => state?.setHasHydrated(true),
+    }
+  )
+)
+```
+
+## Rules
+
+1. Use `devtools` middleware (named stores)
+2. Use `persist` only when data should survive reload
+3. `persist` MUST use `partialize` with an explicit whitelist of the durable fields. Exclude transient flags (`isResizing`, drag/hover state) and `_hasHydrated` from the whitelist, and never spread the whole state (`{ ...state }`) — it leaks actions and transient state into storage
+4. `_hasHydrated` pattern for persisted stores needing hydration tracking
+5. Immutable updates only
+6. `set((state) => ...)` when depending on previous state
+7. Provide `reset()` action
+
+## Outside React
+
+```typescript
+const items = useFeatureStore.getState().items
+useFeatureStore.setState({ items: newItems })
+```