chore: seal Design Vision v1 and monorepo scaffold

Archive the differentiated YuXinGu product docs, AI engineering system,
design contract, and Go/Vue scaffold. Next execution prioritizes Cece-parity
over early innovation (see .ai/product/STRATEGY.md).

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

.ai/design/platform/flutter.md

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+# Platform Contract — Flutter / Native App
+
+Future client. Not in MVP scope unless task explicitly opens it.  
+Design language: [../design-system.md](../design-system.md) · Catalog names stay the same.
+
+---
+
+## Priority
+
+**Performance > Native experience > Visual decoration**
+
+---
+
+## MUST
+
+- Map tokens to `ThemeData` / design token classes — same hex and spacing scale.
+- Native navigation patterns (Material/Cupertino as decided by ADR).
+- Platform permissions (camera, photos, notifications) only with clear UX rationale.
+- 60fps interactions; avoid heavy blur/shadow on low-end devices.
+- Reuse catalog component names (`Button`, `ChatBubble`, `SubscriptionCard`…).
+- Same compliance and domain copy rules.
+
+---
+
+## MUST NOT
+
+- Invent a dark-neon “AI app” skin.
+- Bypass API unlock/membership rules with local flags.
+- Port Web DOM assumptions.
+
+---
+
+## Checklist
+
+- [ ] Token theme 1:1 with `packages/ui`
+- [ ] Catalog parity for screens in scope
+- [ ] Permission + performance considered
+- [ ] ADR if introducing Flutter stack officially

.ai/design/platform/h5.md

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+# Platform Contract — H5 (Mobile Web)
+
+Primary shipping client: `apps/user-h5` (Vue 3 + Vite).  
+Design language: [../design-system.md](../design-system.md) · Components: [../component-catalog.md](../component-catalog.md)
+
+---
+
+## MUST
+
+- Mobile-first; content column `max-width: var(--layout-max-user)` (430px), centered on large screens.
+- Touch targets ≥ 44×44px.
+- Prefer bottom actions (TabBar, AskInputBar, sticky CTA).
+- Safe area: `env(safe-area-inset-bottom)` on TabBar / fixed footers.
+- `user-scalable` / viewport per existing app shell; no desktop-only hover for essentials.
+- Import tokens from `@yuxingu/ui` / `packages/ui` — no page-local brand hex.
+- Data via `src/api` → `@yuxingu/sdk` only (no raw `fetch` in pages).
+- Structure: `pages/` · `components/` · `layouts/` · `stores/` · `router/`.
+- Loading / empty / error on every network view.
+- Report / Decode / Ask: compliance disclaimer.
+
+---
+
+## MUST NOT
+
+- Rely on hover tooltips for critical info.
+- Use `window` APIs that break iOS WeChat/browser without fallback.
+- Invent a second tab IA; tabs = Home / Explore / Ask / Companion / Mine.
+- Grow Legacy root HTML (`yuxingu.html`, `pages/`) for new UI.
+
+---
+
+## Layout notes
+
+- HomeWash: peach gradient body + Decode form + white ContentSheet.
+- Secondary: TopBar + padded content.
+- Keyboard: inputs must not hide primary CTA (scroll / visualViewport aware when needed).
+
+---
+
+## Checklist before Done
+
+- [ ] Tokens only
+- [ ] Catalog component reused or catalog updated
+- [ ] 44px touch
+- [ ] Safe area
+- [ ] States + compliance if needed
+- [ ] `npm run build:h5`

.ai/design/platform/mini-program.md

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+# Platform Contract — WeChat Mini Program
+
+Client: `apps/mini-program`.  
+Design language shared with H5; **implementation is native mini-program**, not Vue SFC reuse.
+
+Tokens: map `packages/ui` values into `app.wxss` / CSS variables supported by the base library — do not fork a second palette.
+
+---
+
+## MUST
+
+- Use Mini Program lifecycle (`onLoad` / `onShow` / …) and `wx` APIs.
+- Native navigation (`wx.navigateTo`, tabBar in `app.json`).
+- Components under `components/`; pages call `services/*` only (same idea as H5 sdk).
+- Support: share (`onShareAppMessage`), user authorization, payment flow when enabled.
+- Touch ≥ 44px; rpx spacing aligned to 4/8/12/16… scale.
+- Same IA tabs and domain copy rules as H5.
+- Paywall / Membership decisions still from API — never local unlock only.
+
+---
+
+## MUST NOT
+
+- `window` / `document` / DOM browser APIs.
+- Import Vue SFCs from `user-h5` as runtime.
+- Duplicate brand colors with new hex values.
+- Build UGC广场 or Consult marketplace in MVP.
+
+---
+
+## Mapping
+
+| H5 | Mini Program |
+|---|---|
+| Vue page | `pages/*` |
+| Pinia | global / store pattern approved in playbook |
+| `@yuxingu/sdk` | same package or thin `services` wrapper |
+| CSS modules | `wxss` + shared token sheet |
+
+---
+
+## Checklist
+
+- [ ] No browser-only APIs
+- [ ] Tokens mapped 1:1
+- [ ] Share / auth / pay paths considered
+- [ ] Catalog names reused

.ai/design/platform/website.md

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+# Platform Contract — Website (Desktop / Marketing Web)
+
+Future or secondary surfaces (landing, SEO pages, admin beyond mobile shell).  
+Brand tokens identical to [../design-system.md](../design-system.md).
+
+---
+
+## MUST
+
+- SEO basics: title / description / semantic headings on marketing pages.
+- Keyboard navigation and visible focus for interactive controls.
+- Hover states allowed as **enhancement**; core actions still work without hover.
+- Large screens: may use sidebar, table, multi-column — do not ship desktop-only flows that leave mobile broken if the same app is responsive.
+- Accessibility: contrast, labels, skip/focus order.
+- Admin (`apps/admin-h5`): denser List/Table OK; still use tokens (primary coral, not random admin blue).
+
+---
+
+## MUST NOT
+
+- Purple SaaS gradient landing that ignores 愈心谷 peach/coral brand.
+- Heavy dashboard chrome on consumer marketing hero (see design-system home budget).
+- Medical / 吉凶 claims in SEO copy.
+
+---
+
+## Breakpoints
+
+| Name | Guide |
+|---|---|
+| Mobile | < 768px — follow H5 patterns |
+| Tablet | 768–1024px — adapt columns, keep touch sizes |
+| Desktop | > 1024px — sidebar / multi-column allowed |
+
+Do not merely scale desktop UI down to mobile.
+
+---
+
+## Checklist
+
+- [ ] Tokens + brand voice
+- [ ] Keyboard / focus
+- [ ] Responsive behavior explicit
+- [ ] SEO for public pages