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/middleware/audit.go

@@ -0,0 +1,114 @@
+package middleware
+
+import (
+	"context"
+	"database/sql"
+	"fmt"
+	"sync"
+	"time"
+
+	_ "github.com/jackc/pgx/v5/stdlib"
+)
+
+// DatabaseAuditEmitter 实现 AuditEmitter 接口，将审计事件存入数据库
+type DatabaseAuditEmitter struct {
+	db  *sql.DB
+	mu  sync.RWMutex
+	now func() time.Time
+}
+
+// NewDatabaseAuditEmitter 创建数据库审计发射器
+func NewDatabaseAuditEmitter(dsn string, now func() time.Time) (*DatabaseAuditEmitter, error) {
+	if now == nil {
+		now = time.Now
+	}
+
+	db, err := sql.Open("pgx", dsn)
+	if err != nil {
+		return nil, fmt.Errorf("failed to open database: %w", err)
+	}
+
+	// 测试连接
+	if err := db.Ping(); err != nil {
+		return nil, fmt.Errorf("failed to ping database: %w", err)
+	}
+
+	emitter := &DatabaseAuditEmitter{
+		db:  db,
+		now: now,
+	}
+
+	// 初始化表
+	if err := emitter.initSchema(); err != nil {
+		return nil, fmt.Errorf("failed to init schema: %w", err)
+	}
+
+	return emitter, nil
+}
+
+// initSchema 创建审计表
+func (e *DatabaseAuditEmitter) initSchema() error {
+	schema := `
+	CREATE TABLE IF NOT EXISTS token_audit_events (
+		event_id VARCHAR(64) PRIMARY KEY,
+		event_name VARCHAR(128) NOT NULL,
+		request_id VARCHAR(128) NOT NULL,
+		token_id VARCHAR(128),
+		subject_id VARCHAR(128),
+		route VARCHAR(256) NOT NULL,
+		result_code VARCHAR(64) NOT NULL,
+		client_ip VARCHAR(64),
+		created_at TIMESTAMP NOT NULL DEFAULT NOW()
+	);
+
+	CREATE INDEX IF NOT EXISTS idx_token_audit_request_id ON token_audit_events(request_id);
+	CREATE INDEX IF NOT EXISTS idx_token_audit_token_id ON token_audit_events(token_id);
+	CREATE INDEX IF NOT EXISTS idx_token_audit_subject_id ON token_audit_events(subject_id);
+	CREATE INDEX IF NOT EXISTS idx_token_audit_created_at ON token_audit_events(created_at);
+	`
+	_, err := e.db.Exec(schema)
+	return err
+}
+
+// Emit 实现 AuditEmitter 接口
+func (e *DatabaseAuditEmitter) Emit(_ context.Context, event AuditEvent) error {
+	if event.EventID == "" {
+		event.EventID = fmt.Sprintf("evt-%d", e.now().UnixNano())
+	}
+	if event.CreatedAt.IsZero() {
+		event.CreatedAt = e.now()
+	}
+
+	query := `
+		INSERT INTO token_audit_events (event_id, event_name, request_id, token_id, subject_id, route, result_code, client_ip, created_at)
+		VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9)
+	`
+	_, err := e.db.Exec(query,
+		event.EventID,
+		event.EventName,
+		event.RequestID,
+		nullString(event.TokenID),
+		nullString(event.SubjectID),
+		event.Route,
+		event.ResultCode,
+		nullString(event.ClientIP),
+		event.CreatedAt,
+	)
+	return err
+}
+
+// Close 关闭数据库连接
+func (e *DatabaseAuditEmitter) Close() error {
+	if e.db != nil {
+		return e.db.Close()
+	}
+	return nil
+}
+
+// nullString 安全处理空字符串
+func nullString(s string) sql.NullString {
+	if s == "" {
+		return sql.NullString{}
+	}
+	return sql.NullString{String: s, Valid: true}
+}