feat(01-01): create Zustand store with 6 slices, IPC batcher, and unit tests

- Install zustand 5.x and immer 11.x dependencies
- Create 6 Zustand slices: navigation, company, selection, ui, communication, social
- Create combined store with devtools + immer middleware
- Create IPC event batcher with 50ms debounce window (schedule/flush/dispose)
- Create typed selector hooks for narrow state subscriptions
- Add 14 unit tests covering store initialization, slice behaviors, and batcher timing

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/renderer/state/slices/ui.ts

@@ -0,0 +1,57 @@
+import type { StateCreator } from "zustand";
+import type { AppState } from "../store";
+import type { AppLocale } from "@shared/locale";
+import { DEFAULT_LOCALE } from "@shared/locale";
+
+export interface UiSlice {
+  locale: AppLocale;
+  showOnboarding: boolean;
+  initialOnboardingLocked: boolean;
+  confirmDeleteCompanyId: string | null;
+  taskViewMode: "list" | "kanban";
+  logRevision: number;
+  setLocale: (locale: AppLocale) => void;
+  setShowOnboarding: (show: boolean) => void;
+  setInitialOnboardingLocked: (locked: boolean) => void;
+  setConfirmDeleteCompanyId: (id: string | null) => void;
+  setTaskViewMode: (mode: "list" | "kanban") => void;
+  incrementLogRevision: () => void;
+}
+
+export const createUiSlice: StateCreator<
+  AppState,
+  [["zustand/immer", never]],
+  [],
+  UiSlice
+> = (set) => ({
+  locale: DEFAULT_LOCALE,
+  showOnboarding: false,
+  initialOnboardingLocked: false,
+  confirmDeleteCompanyId: null,
+  taskViewMode: "list",
+  logRevision: 0,
+  setLocale: (locale) =>
+    set((state) => {
+      state.locale = locale;
+    }),
+  setShowOnboarding: (show) =>
+    set((state) => {
+      state.showOnboarding = show;
+    }),
+  setInitialOnboardingLocked: (locked) =>
+    set((state) => {
+      state.initialOnboardingLocked = locked;
+    }),
+  setConfirmDeleteCompanyId: (id) =>
+    set((state) => {
+      state.confirmDeleteCompanyId = id;
+    }),
+  setTaskViewMode: (mode) =>
+    set((state) => {
+      state.taskViewMode = mode;
+    }),
+  incrementLogRevision: () =>
+    set((state) => {
+      state.logRevision += 1;
+    }),
+});