feat(renderer): command store persists userBindings (Phase 6)

- add userBindings map (commandId -> combo string)
- setUserBinding / clearUserBinding / getUserBinding actions
- persist middleware with partialize: handlers are runtime-only,
  userBindings are serialized
- TDD: 7 persistence tests + existing 10 command-store tests still pass
- 162/162 total tests pass

src/renderer/stores/command-store.ts

@@ -1,35 +1,66 @@
 import { create } from 'zustand';
+import { persist } from 'zustand/middleware';
 
 export type CommandId = string;
 
 export type CommandHandler = (args?: unknown) => void | Promise<void>;
 
+/**
+ * User-customizable key binding for a command.
+ * Format: same as useShortcut combo ('mod+s', 'mod+shift+s', etc.)
+ * Undefined means "use the default binding" (if any).
+ */
+export type UserBindings = Record<string, string>;
+
 interface CommandState {
   handlers: Record<string, CommandHandler>;
+  userBindings: UserBindings;
   register: (id: CommandId, handler: CommandHandler) => void;
   registerMany: (handlers: Record<string, CommandHandler>) => void;
   unregister: (id: CommandId) => void;
   dispatch: (id: CommandId, args?: unknown) => void;
   get: (id: CommandId) => CommandHandler | undefined;
+  setUserBinding: (id: CommandId, combo: string) => void;
+  clearUserBinding: (id: CommandId) => void;
+  getUserBinding: (id: CommandId) => string | undefined;
 }
 
-export const useCommandStore = create<CommandState>((set, get) => ({
-  handlers: {},
-  register: (id, handler) =>
-    set((s) => ({ handlers: { ...s.handlers, [id]: handler } })),
-  registerMany: (handlers) =>
-    set((s) => ({ handlers: { ...s.handlers, ...handlers } })),
-  unregister: (id) =>
-    set((s) => {
-      const next = { ...s.handlers };
-      delete next[id];
-      return { handlers: next };
+export const useCommandStore = create<CommandState>()(
+  persist(
+    (set, get) => ({
+      handlers: {},
+      userBindings: {},
+      register: (id, handler) =>
+        set((s) => ({ handlers: { ...s.handlers, [id]: handler } })),
+      registerMany: (handlers) =>
+        set((s) => ({ handlers: { ...s.handlers, ...handlers } })),
+      unregister: (id) =>
+        set((s) => {
+          const next = { ...s.handlers };
+          delete next[id];
+          return { handlers: next };
+        }),
+      dispatch: (id, args) => {
+        const handler = get().handlers[id];
+        if (handler) {
+          void handler(args);
+        }
+      },
+      get: (id) => get().handlers[id],
+      setUserBinding: (id, combo) =>
+        set((s) => ({ userBindings: { ...s.userBindings, [id]: combo } })),
+      clearUserBinding: (id) =>
+        set((s) => {
+          const next = { ...s.userBindings };
+          delete next[id];
+          return { userBindings: next };
+        }),
+      getUserBinding: (id) => get().userBindings[id],
     }),
-  dispatch: (id, args) => {
-    const handler = get().handlers[id];
-    if (handler) {
-      void handler(args);
+    {
+      name: 'mc-command-store',
+      // Only persist user-customizable bindings; handlers are runtime-only.
+      partialize: (state) => ({ userBindings: state.userBindings }),
     }
-  },
-  get: (id) => get().handlers[id],
-}));
+  )
+);