feat(epic2): Implement core authentication and authorization services

- Implement Audit Service (2.5)
  - gRPC server with Record and Query operations
  - Database persistence with audit schema
  - Service registry integration
  - Entry point: cmd/audit-service

- Implement Identity Service (2.2)
  - User CRUD operations
  - Password hashing with argon2id
  - Email verification and password reset flows
  - Entry point: cmd/identity-service
  - Fix package naming conflicts in user_service.go

- Implement Auth Service (2.1)
  - JWT token generation and validation
  - Login, RefreshToken, ValidateToken, Logout RPCs
  - Integration with Identity Service
  - Entry point: cmd/auth-service
  - Note: RefreshToken entity needs Ent generation

- Implement Authz Service (2.3, 2.4)
  - Permission checking and authorization
  - User roles and permissions retrieval
  - RBAC-based authorization
  - Entry point: cmd/authz-service

- Implement gRPC clients for all services
  - Auth, Identity, Authz, and Audit clients
  - Service discovery integration
  - Full gRPC communication

- Add service configurations to config/default.yaml
- Create SUMMARY.md with implementation details and testing instructions
- Fix compilation errors in Identity Service (password package conflicts)
- All services build successfully and tests pass

go.mod

@@ -10,6 +10,7 @@ require (
 	github.com/lib/pq v1.10.9
 	github.com/prometheus/client_golang v1.23.2
 	github.com/spf13/viper v1.18.0
+	github.com/stretchr/testify v1.11.1
 	go.opentelemetry.io/contrib/instrumentation/github.com/gin-gonic/gin/otelgin v0.63.0
 	go.opentelemetry.io/otel v1.38.0
 	go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp v1.38.0
@@ -18,7 +19,9 @@ require (
 	go.opentelemetry.io/otel/trace v1.38.0
 	go.uber.org/fx v1.24.0
 	go.uber.org/zap v1.26.0
+	golang.org/x/crypto v0.43.0
 	google.golang.org/grpc v1.75.0
+	google.golang.org/protobuf v1.36.8
 )
 
 require (
@@ -46,6 +49,7 @@ require (
 	github.com/go-playground/validator/v10 v10.27.0 // indirect
 	github.com/go-viper/mapstructure/v2 v2.4.0 // indirect
 	github.com/goccy/go-json v0.10.5 // indirect
+	github.com/golang-jwt/jwt/v5 v5.3.0 // indirect
 	github.com/google/go-cmp v0.7.0 // indirect
 	github.com/grpc-ecosystem/grpc-gateway/v2 v2.27.2 // indirect
 	github.com/hashicorp/errwrap v1.1.0 // indirect
@@ -81,7 +85,6 @@ require (
 	github.com/spf13/afero v1.11.0 // indirect
 	github.com/spf13/cast v1.6.0 // indirect
 	github.com/spf13/pflag v1.0.5 // indirect
-	github.com/stretchr/testify v1.11.1 // indirect
 	github.com/subosito/gotenv v1.6.0 // indirect
 	github.com/twitchyliquid64/golang-asm v0.15.1 // indirect
 	github.com/ugorji/go/codec v1.3.0 // indirect
@@ -95,15 +98,13 @@ require (
 	go.uber.org/multierr v1.10.0 // indirect
 	go.yaml.in/yaml/v2 v2.4.2 // indirect
 	golang.org/x/arch v0.20.0 // indirect
-	golang.org/x/crypto v0.41.0 // indirect
 	golang.org/x/exp v0.0.0-20250808145144-a408d31f581a // indirect
-	golang.org/x/mod v0.27.0 // indirect
-	golang.org/x/net v0.43.0 // indirect
-	golang.org/x/sys v0.35.0 // indirect
-	golang.org/x/text v0.28.0 // indirect
+	golang.org/x/mod v0.28.0 // indirect
+	golang.org/x/net v0.45.0 // indirect
+	golang.org/x/sys v0.37.0 // indirect
+	golang.org/x/text v0.30.0 // indirect
 	google.golang.org/genproto/googleapis/api v0.0.0-20250825161204-c5933d9347a5 // indirect
 	google.golang.org/genproto/googleapis/rpc v0.0.0-20250825161204-c5933d9347a5 // indirect
-	google.golang.org/protobuf v1.36.8 // indirect
 	gopkg.in/ini.v1 v1.67.0 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 )