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>

AGENTS.md

@@ -0,0 +1,44 @@
+# AGENTS.md — AI System Entry
+
+You are the software engineer for **愈心谷 (YuXinGu)**.
+
+This file is for AI agents.
+
+## Load order (every task)
+
+1. `.ai/ai-contract.md`
+2. `.ai/constitution.md`
+3. `.ai/architecture.md`
+4. `.ai/domain.md` (+ product/API tasks: `domain/domain-map.md`)
+5. `.ai/forbidden.md`
+6. `.ai/file-map.md` + `.ai/workflow.md`
+7. Task rules: `.ai/coding.md` / `api.md` / `database.md` / `ui.md` / `security.md` / …
+8. **Product scope / PRD slicing:** `.ai/product/feature-map.md` (竞品对照: `product/cece-feature-map.md`)
+9. **Any UI work:** `.ai/design/design-system.md` + `component-catalog.md` + matching `design/platform/*.md` (H5 default)
+10. Matching **ADR** in `.ai/adr/` before changing stack or API style
+11. Prefer **patterns/** + **examples/** + **playbooks/** over inventing structure
+12. Before Done: `.ai/review.md` + `.ai/definition-of-done.md` + `.ai/checklists/*`
+13. Verify via `.ai/commands.md`
+14. `prompts/` are optional helpers — not a substitute for rules above
+
+## Hard constraints
+
+- Never violate architecture or Accepted ADRs.
+- Never invent APIs, DB tables, or domain synonyms.
+- Never guess requirements — **ASK FIRST**.
+- Never modify files outside the current task.
+- New code only under `apps/` and `packages/` (unless legacy migration task).
+- One concern per change set. Function ≤50 lines. File ≤400 lines.
+- Print the Review block when a coding task finishes.
+
+## Cursor
+
+`.cursor/` is an Agent Runtime view of this system via symlinks. Edit `.ai/` only.
+
+## Growth
+
+Do not invent Phase 2/3 folders (graph/mcp/skills/anti-patterns/…) unless `ROADMAP.md` says so and the task asks. Prefer improving patterns/examples/playbooks.
+
+## Product one-liner
+
+Birthday → Profile (digital personality + constitution) → Companion / Ask retention → Membership & Report unlock → Consult later. Compliant lifestyle wording only.