docs(uiux): UIUX 设计方案大改 + 5 份作业指导书对齐 + 开发任务文档

- UIUX 文档：填充 19 个缺口（多主体画像/健康度/AI+看板/增长域/洞察域/创始人端/OODA/助推/商密）
- UIUX 文档：插入 6 个新章节（十四~十九），旧章节重编号为二十~三十一，更新目录和交叉引用
- 作业指导书 x5：导航改为 6 域分组，新增 Context Bar/工作模式/Insight Rail/决策线程/多工作区等 UI 概念
- 新建 docs/2-task-uiux.md：50 个代码落地开发任务，按 P0-P6 分优先级 + 8 Sprint 规划
- 后端/前端：大量新增模型、路由、组件（来自之前 Phase 开发）

backend/app/routers/peer_circles.py

@@ -0,0 +1,43 @@
+"""Peer Learning Circles 路由。"""
+
+from fastapi import APIRouter, Depends, Query
+from sqlalchemy import select
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.core.database import get_db
+from app.core.dependencies import get_current_user
+from app.models.peer_circle import PeerLearningCircle
+from app.models.user import User
+from app.schemas.common import ApiResponse, success
+from app.services.peer_matching import match_founders
+
+router = APIRouter(prefix="/peer-circles", tags=["peer-circles"])
+
+
+@router.get("", response_model=ApiResponse[list])
+async def list_circles(db: AsyncSession = Depends(get_db), user: User = Depends(get_current_user)):
+    """获取 Peer Learning Circle 列表。"""
+    result = await db.execute(
+        select(PeerLearningCircle).where(PeerLearningCircle.tenant_id == user.tenant_id)
+    )
+    items = result.scalars().all()
+    return success(data=[
+        {
+            "id": str(i.id),
+            "topic": i.topic,
+            "description": i.description,
+            "members": i.members,
+            "discussion_framework": i.discussion_framework,
+            "conclusions": i.conclusions,
+            "action_commitments": i.action_commitments,
+            "status": i.status,
+        }
+        for i in items
+    ])
+
+
+@router.post("/match", response_model=ApiResponse[dict])
+async def match_peer_circle(req: dict, user: User = Depends(get_current_user)):
+    """AI 匹配创始人。"""
+    result = await match_founders(req.get("founders_context", ""))
+    return success(data=result)