Initial commit: AI-driven visual novel scaffold

- Monorepo (pnpm workspace): apps/web + packages/{types,ai-client,engine}
- Next.js 16 web app with three-stage AI orchestration
- Three independently configurable providers: text LLM, image generator, vision model
- Warm minimalist editorial UI design
- One-click Vercel deploy ready

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

packages/types/src/index.ts

@@ -0,0 +1,74 @@
+export type UIElementKind = "choice" | "menu" | "item" | "custom";
+
+export type UIElement = {
+  id: string;
+  kind: UIElementKind;
+  label: string;
+  hint?: string;
+};
+
+export type StoryFrame = {
+  id: string;
+  narration?: string;
+  speaker?: string;
+  line?: string;
+  scenePrompt: string;
+  uiElements: UIElement[];
+};
+
+export type ClickIntent = {
+  targetId: string | null;
+  targetLabel: string | null;
+  reasoning: string;
+  freeformAction?: string;
+};
+
+export type HistoryEntry = {
+  frame: StoryFrame;
+  click?: { x: number; y: number };
+  intent?: ClickIntent;
+};
+
+export type Session = {
+  id: string;
+  createdAt: number;
+  worldSetting: string;
+  styleGuide: string;
+  history: HistoryEntry[];
+};
+
+export type ProviderConfig = {
+  baseUrl: string;
+  apiKey: string;
+  model: string;
+};
+
+export type EngineConfig = {
+  text: ProviderConfig;
+  image: ProviderConfig;
+  vision: ProviderConfig;
+};
+
+export type StartRequest = {
+  worldSetting: string;
+  styleGuide: string;
+};
+
+export type StartResponse = {
+  sessionId: string;
+  frame: StoryFrame;
+  imageBase64: string;
+};
+
+export type InteractRequest = {
+  session: Session;
+  prevImageBase64: string;
+  click: { x: number; y: number };
+};
+
+export type InteractResponse = {
+  session: Session;
+  frame: StoryFrame;
+  imageBase64: string;
+  intent: ClickIntent;
+};