refactor: flatten monorepo to single web package (#12)

Flatten the pnpm monorepo (apps/web + packages/*) into a single web package at the repo root.

- Move app/lib/components/scripts/public to root; drop apps/web and packages/* wrappers
- Rewrite tsconfig paths (@infiplot/*) to ./lib/*; turbopack.root = __dirname
- Update Vercel (no root-directory) and Cloudflare (pnpm build:cf at root) deploy paths
- Regenerate pnpm-lock.yaml to drop stale workspace importers
- Bump engines.node to >=22 to match wrangler

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

lib/presets.ts

@@ -0,0 +1,37 @@
+export type Preset = {
+  id: string;
+  title: string;
+  blurb: string;
+  worldSetting: string;
+  styleGuide: string;
+};
+
+export const PRESETS: Preset[] = [
+  {
+    id: "highschool",
+    title: "六月雨季",
+    blurb: "县城高中，转学生，未送出的伞。",
+    worldSetting:
+      "故事发生在 1990 年代末的中国南方县城高中。主角是高三转学生，在多雨的六月遇到一个总在天台读诗的同学。剧情慢热、含蓄、带点伤感。",
+    styleGuide:
+      "Anime visual novel style, soft watercolor lighting, warm afternoon palette, classic Japanese galgame dialogue panel.",
+  },
+  {
+    id: "cyberpunk",
+    title: "雨夜霓虹",
+    blurb: "失忆的私家侦探，一通陌生来电。",
+    worldSetting:
+      "2087 年的雨夜东亚特区。主角是一个刚从昏迷中醒来、丢失了三天记忆的私家侦探。他的电话响了，对面是一个声称认识他的女人。",
+    styleGuide:
+      "Cinematic cyberpunk realism, neon reflections on wet streets, blade-runner palette, transparent neon HUD interface elements.",
+  },
+  {
+    id: "stickfigure",
+    title: "火柴人冒险",
+    blurb: "一支铅笔，一个世界，全靠涂改。",
+    worldSetting:
+      "你是一个用铅笔画在格子本上的火柴人，刚意识到自己活在一个学生的草稿纸里。本子的边缘正在被橡皮擦逐渐抹去，你必须想办法逃出去。",
+    styleGuide:
+      "Hand-drawn pencil sketch on grid paper, stick figures, rough doodle UI elements, eraser smudges, notebook aesthetic.",
+  },
+];