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/decision_sentinels.py

@@ -0,0 +1,68 @@
+"""决策前哨路由：CRUD + 场景分析查询。"""
+
+from fastapi import APIRouter, Depends, HTTPException, Query, status
+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.company import Company
+from app.models.decision_sentinel import DecisionSentinel
+from app.models.user import User
+from app.schemas.common import ApiResponse, success
+from app.services.decision_sentinel_agent import analyze_scenarios, identify_decision_points
+
+router = APIRouter(prefix="/decision-sentinels", tags=["decision-sentinels"])
+
+
+@router.get("", response_model=ApiResponse[list])
+async def list_sentinels(
+    company_id: str | None = Query(default=None),
+    db: AsyncSession = Depends(get_db),
+    user: User = Depends(get_current_user),
+):
+    """获取决策前哨列表。"""
+    query = (
+        select(DecisionSentinel)
+        .join(Company, DecisionSentinel.company_id == Company.id)
+        .where(Company.tenant_id == user.tenant_id)
+    )
+    if company_id:
+        query = query.where(DecisionSentinel.company_id == company_id)
+    result = await db.execute(query.order_by(DecisionSentinel.identified_at.desc()))
+    items = result.scalars().all()
+    return success(data=[
+        {
+            "id": str(i.id),
+            "company_id": str(i.company_id),
+            "decision_type": i.decision_type,
+            "title": i.title,
+            "description": i.description,
+            "signals": i.signals,
+            "scenarios": i.scenarios,
+            "status": i.status,
+            "identified_at": i.identified_at.isoformat(),
+        }
+        for i in items
+    ])
+
+
+@router.post("/identify", response_model=ApiResponse[list])
+async def identify_sentinels(
+    req: dict,
+    user: User = Depends(get_current_user),
+):
+    """AI 识别决策岔路口。"""
+    points = await identify_decision_points(req.get("company_context", ""))
+    return success(data=points)
+
+
+@router.post("/{sentinel_id}/analyze", response_model=ApiResponse[dict])
+async def analyze_sentinel_scenarios(
+    sentinel_id: str,
+    req: dict,
+    user: User = Depends(get_current_user),
+):
+    """AI 生成场景分析。"""
+    scenarios = await analyze_scenarios(req.get("decision", {}))
+    return success(data=scenarios)