docs: freeze YuXinGu lexicon, journey, and P1 engineering sources

Establish product language contract, user journey with dual growth engines,
ERD/OpenAPI/Go boundaries, and H5 routes (/profile, /portrait, /relation,
/membership) before P1 implementation.

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

.ai/file-map.md

@@ -58,10 +58,14 @@ Rules, ADR, patterns, examples, playbooks, checklists. Not runtime code.
 
 | Path | Owns |
 |---|---|
-| `product/feature-map.md` | 愈心谷 L0/L1/L2 + MVP 标记 |
-| `product/cece-feature-map.md` | 测测竞品合并 Feature Tree |
-| `domain/domain-map.md` | Bounded contexts / aggregates / ER |
-| `domain.md` | Ubiquitous terms only |
+| `product/lexicon.md` | 产品中文语言契约（最高优先级） |
+| `product/user-journey.md` | 转化路径 |
+| `product/page-tree.md` | H5 路由冻结 |
+| `product/feature-map.md` | 能力树 · 五 Tab 冻结 |
+| `product/ENGINEERING-FREEZE.md` | P1 真源索引 |
+| `domain/domain-map.md` + `erd.md` | Contexts + 表结构 |
+| `architecture/go-services.md` | Go 包边界 |
+| `domain.md` | Tech ↔ 用户名 |
 
 ### .ai/design/