refactor: Align Epic 0 & Epic 1 with true microservices architecture

Refactor core kernel and infrastructure to support true microservices
architecture where services are independently deployable.

Phase 1: Core Kernel Cleanup
- Remove database provider from CoreModule (services create their own)
- Update ProvideHealthRegistry to not depend on database
- Add schema support to database client (NewClientWithSchema)
- Update main entry point to remove database dependency
- Core kernel now provides only: config, logger, error bus, health, metrics, tracer, service registry

Phase 2: Service Registry Implementation
- Create ServiceRegistry interface (pkg/registry/registry.go)
- Implement Consul registry (internal/registry/consul/consul.go)
- Add Consul dependency (github.com/hashicorp/consul/api)
- Add registry configuration to config/default.yaml
- Add ProvideServiceRegistry() to DI container

Phase 3: Service Client Interfaces
- Create service client interfaces:
  - pkg/services/auth.go - AuthServiceClient
  - pkg/services/identity.go - IdentityServiceClient
  - pkg/services/authz.go - AuthzServiceClient
  - pkg/services/audit.go - AuditServiceClient
- Create ServiceClientFactory (internal/client/factory.go)
- Create stub gRPC client implementations (internal/client/grpc/)
- Add ProvideServiceClientFactory() to DI container

Phase 4: gRPC Service Definitions
- Create proto files for all core services:
  - api/proto/auth.proto
  - api/proto/identity.proto
  - api/proto/authz.proto
  - api/proto/audit.proto
- Add generate-proto target to Makefile

Phase 5: API Gateway Implementation
- Create API Gateway service entry point (cmd/api-gateway/main.go)
- Create Gateway implementation (services/gateway/gateway.go)
- Add gateway configuration to config/default.yaml
- Gateway registers with Consul and routes requests to backend services

All code compiles successfully. Core services (Auth, Identity, Authz, Audit)
will be implemented in Epic 2 using these foundations.

go.mod

@@ -1,6 +1,6 @@
 module git.dcentral.systems/toolz/goplt
 
-go 1.24
+go 1.25.3
 
 require (
 	entgo.io/ent v0.14.5
@@ -23,6 +23,7 @@ require (
 	ariga.io/atlas v0.32.1-0.20250325101103-175b25e1c1b9 // indirect
 	github.com/agext/levenshtein v1.2.3 // indirect
 	github.com/apparentlymart/go-textseg/v15 v15.0.0 // indirect
+	github.com/armon/go-metrics v0.4.1 // indirect
 	github.com/beorn7/perks v1.0.1 // indirect
 	github.com/bmatcuk/doublestar v1.3.4 // indirect
 	github.com/bytedance/sonic v1.14.0 // indirect
@@ -30,6 +31,7 @@ require (
 	github.com/cenkalti/backoff/v5 v5.0.3 // indirect
 	github.com/cespare/xxhash/v2 v2.3.0 // indirect
 	github.com/cloudwego/base64x v0.1.6 // indirect
+	github.com/fatih/color v1.16.0 // indirect
 	github.com/fsnotify/fsnotify v1.7.0 // indirect
 	github.com/gabriel-vasile/mimetype v1.4.10 // indirect
 	github.com/gin-contrib/sse v1.1.0 // indirect
@@ -39,16 +41,28 @@ require (
 	github.com/go-playground/locales v0.14.1 // indirect
 	github.com/go-playground/universal-translator v0.18.1 // indirect
 	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/google/go-cmp v0.7.0 // indirect
 	github.com/grpc-ecosystem/grpc-gateway/v2 v2.27.2 // indirect
+	github.com/hashicorp/consul/api v1.33.0 // indirect
+	github.com/hashicorp/errwrap v1.1.0 // indirect
+	github.com/hashicorp/go-cleanhttp v0.5.2 // indirect
+	github.com/hashicorp/go-hclog v1.5.0 // indirect
+	github.com/hashicorp/go-immutable-radix v1.3.1 // indirect
+	github.com/hashicorp/go-multierror v1.1.1 // indirect
+	github.com/hashicorp/go-rootcerts v1.0.2 // indirect
+	github.com/hashicorp/golang-lru v0.5.4 // indirect
 	github.com/hashicorp/hcl v1.0.0 // indirect
 	github.com/hashicorp/hcl/v2 v2.18.1 // indirect
+	github.com/hashicorp/serf v0.10.1 // indirect
 	github.com/json-iterator/go v1.1.12 // indirect
 	github.com/klauspost/cpuid/v2 v2.3.0 // indirect
 	github.com/leodido/go-urn v1.4.0 // indirect
 	github.com/magiconair/properties v1.8.7 // indirect
+	github.com/mattn/go-colorable v0.1.13 // indirect
 	github.com/mattn/go-isatty v0.0.20 // indirect
+	github.com/mitchellh/go-homedir v1.1.0 // indirect
 	github.com/mitchellh/go-wordwrap v1.0.1 // indirect
 	github.com/mitchellh/mapstructure v1.5.0 // indirect
 	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
@@ -78,8 +92,8 @@ require (
 	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 v0.0.0-20230905200255-921286631fa9 // indirect
-	golang.org/x/mod v0.26.0 // 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