feat(P1/P2): 完成TDD开发及P1/P2设计文档

## 设计文档
- multi_role_permission_design: 多角色权限设计 (CONDITIONAL GO)
- audit_log_enhancement_design: 审计日志增强 (CONDITIONAL GO)
- routing_strategy_template_design: 路由策略模板 (CONDITIONAL GO)
- sso_saml_technical_research: SSO/SAML调研 (CONDITIONAL GO)
- compliance_capability_package_design: 合规能力包设计 (CONDITIONAL GO)

## TDD开发成果
- IAM模块: supply-api/internal/iam/ (111个测试)
- 审计日志模块: supply-api/internal/audit/ (40+测试)
- 路由策略模块: gateway/internal/router/ (33+测试)
- 合规能力包: gateway/internal/compliance/ + scripts/ci/compliance/

## 规范文档
- parallel_agent_output_quality_standards: 并行Agent产出质量规范
- project_experience_summary: 项目经验总结 (v2)
- 2026-04-02-p1-p2-tdd-execution-plan: TDD执行计划

## 评审报告
- 5个CONDITIONAL GO设计文档评审报告
- fix_verification_report: 修复验证报告
- full_verification_report: 全面质量验证报告
- tdd_module_quality_verification: TDD模块质量验证
- tdd_execution_summary: TDD执行总结

依据: Superpowers执行框架 + TDD规范

gateway/internal/router/strategy/ab_strategy.go

@@ -0,0 +1,71 @@
+package strategy
+
+import (
+	"fmt"
+	"hash/fnv"
+	"time"
+)
+
+// ABStrategy A/B测试策略
+type ABStrategy struct {
+	controlStrategy     *RoutingStrategyTemplate
+	experimentStrategy  *RoutingStrategyTemplate
+	trafficSplit        int    // 实验组流量百分比 (0-100)
+	bucketKey           string // 分桶key
+	experimentID        string
+	startTime           *time.Time
+	endTime             *time.Time
+}
+
+// NewABStrategy 创建A/B测试策略
+func NewABStrategy(control, experiment *RoutingStrategyTemplate, split int, bucketKey string) *ABStrategy {
+	return &ABStrategy{
+		controlStrategy:    control,
+		experimentStrategy: experiment,
+		trafficSplit:       split,
+		bucketKey:          bucketKey,
+	}
+}
+
+// ShouldApplyToRequest 判断请求是否应该使用实验组策略
+func (a *ABStrategy) ShouldApplyToRequest(req *RoutingRequest) bool {
+	// 检查时间范围
+	now := time.Now()
+	if a.startTime != nil && now.Before(*a.startTime) {
+		return false
+	}
+	if a.endTime != nil && now.After(*a.endTime) {
+		return false
+	}
+
+	// 一致性哈希分桶
+	bucket := a.hashString(fmt.Sprintf("%s:%s", a.bucketKey, req.UserID)) % 100
+	return bucket < a.trafficSplit
+}
+
+// hashString 计算字符串哈希值 (用于一致性分桶)
+func (a *ABStrategy) hashString(s string) int {
+	h := fnv.New32a()
+	h.Write([]byte(s))
+	return int(h.Sum32())
+}
+
+// GetControlStrategy 获取对照组策略
+func (a *ABStrategy) GetControlStrategy() *RoutingStrategyTemplate {
+	return a.controlStrategy
+}
+
+// GetExperimentStrategy 获取实验组策略
+func (a *ABStrategy) GetExperimentStrategy() *RoutingStrategyTemplate {
+	return a.experimentStrategy
+}
+
+// RoutingStrategyTemplate 路由策略模板
+type RoutingStrategyTemplate struct {
+	ID          string
+	Name        string
+	Type        string
+	Priority    int
+	Enabled     bool
+	Description string
+}