feat(npcs): add campaign NPCs with relation graph and session overlay

Add a dedicated NPC editor window, directed relations, control/presentation avatar overlay, and ru/en help for the new section.

Co-authored-by: Cursor <cursoragent@cursor.com>

app/renderer/shared/npcs/useNpcsOverlayState.ts

@@ -0,0 +1,31 @@
+import { useEffect, useState } from 'react';
+
+import { ipcChannels } from '../../../shared/ipc/contracts';
+import type { NpcsOverlayEvent, NpcsOverlayState } from '../../../shared/types';
+import { getDndApi } from '../dndApi';
+
+export function useNpcsOverlayState(): readonly [
+  NpcsOverlayState | null,
+  { dispatch: (event: NpcsOverlayEvent) => Promise<void> },
+] {
+  const api = getDndApi();
+  const [state, setState] = useState<NpcsOverlayState | null>(null);
+
+  useEffect(() => {
+    void api.invoke(ipcChannels.npcsOverlay.getState, {}).then((r) => {
+      setState(r.state);
+    });
+    return api.on(ipcChannels.npcsOverlay.stateChanged, ({ state: next }) => {
+      setState(next);
+    });
+  }, [api]);
+
+  return [
+    state,
+    {
+      dispatch: async (event) => {
+        await api.invoke(ipcChannels.npcsOverlay.dispatch, { event });
+      },
+    },
+  ] as const;
+}