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/editor/graph/sceneCardById.test.ts

@@ -23,6 +23,8 @@ function minimalProject(overrides: Partial<Project>): Project {
     assets: {},
     campaignAudios: [],
     materials: [],
+    npcs: [],
+    npcRelations: [],
     currentSceneId: null,
     currentGraphNodeId: null,
     sceneGraphNodes: [],