feat(ai): KDIGO 透析专用风险评分器 — Phase 1 关怀引擎 MVP 第二步

新增 DialysisRiskScorer：12 条 KDIGO 规则覆盖 Kt/V、血磷、血钾、血红蛋白、
体重增长、eGFR、白蛋白，含 KDIGO CKD G1-G5 分期。同步暴露
POST /ai/dialysis/risk-assessment 端点。76 个测试全部通过。

crates/erp-ai/src/handler/mod.rs

@@ -487,6 +487,22 @@ where
     Ok(Json(ApiResponse::ok(result)))
 }
 
+// === 透析风险评估（KDIGO 规则） ===
+
+pub async fn assess_dialysis_risk<S>(
+    Extension(ctx): Extension<TenantContext>,
+    Json(body): Json<crate::service::dialysis_risk_scorer::DialysisLabInput>,
+) -> Result<Json<ApiResponse<crate::service::dialysis_risk_scorer::DialysisRiskAssessment>>, erp_core::error::AppError>
+where
+    AiState: FromRef<S>,
+    S: Clone + Send + Sync + 'static,
+{
+    require_permission(&ctx, "ai.analysis.manage")?;
+    let scorer = crate::service::dialysis_risk_scorer::DialysisRiskScorer::new();
+    let result = scorer.assess(&body);
+    Ok(Json(ApiResponse::ok(result)))
+}
+
 // === SSE 流构建辅助 ===
 
 fn build_sse_stream(