feat(epic1): implement core infrastructure (stories 1.1-1.5)

Implemented Epic 1 core kernel and infrastructure stories:

Story 1.1: Enhanced DI Container
- Added providers for database, health, metrics, and error bus
- Extended CoreModule to include all core services

Story 1.2: Database Layer with Ent ORM
- Created Ent schema for User, Role, Permission, AuditLog entities
- Implemented many-to-many relationships (User-Role, Role-Permission)
- Created database client wrapper with connection pooling
- Added database provider to DI container with migration support

Story 1.3: Health Monitoring and Metrics System
- Implemented health check registry and interface
- Added database health checker
- Created Prometheus metrics system with HTTP instrumentation
- Added health and metrics providers to DI container

Story 1.4: Error Handling and Error Bus
- Implemented channel-based error bus
- Created ErrorPublisher interface
- Added error bus provider with lifecycle management

Story 1.5: HTTP Server Foundation
- Created HTTP server with Gin framework
- Implemented comprehensive middleware stack:
  - Request ID generation
  - Structured logging
  - Panic recovery with error bus integration
  - Prometheus metrics collection
  - CORS support
- Registered core routes: /healthz, /ready, /metrics
- Integrated with FX lifecycle for graceful shutdown

All components are integrated via DI container and ready for use.

internal/ent/rolepermission/rolepermission.go

@@ -0,0 +1,114 @@
+// Code generated by ent, DO NOT EDIT.
+
+package rolepermission
+
+import (
+	"entgo.io/ent/dialect/sql"
+	"entgo.io/ent/dialect/sql/sqlgraph"
+)
+
+const (
+	// Label holds the string label denoting the rolepermission type in the database.
+	Label = "role_permission"
+	// FieldID holds the string denoting the id field in the database.
+	FieldID = "id"
+	// FieldRoleID holds the string denoting the role_id field in the database.
+	FieldRoleID = "role_id"
+	// FieldPermissionID holds the string denoting the permission_id field in the database.
+	FieldPermissionID = "permission_id"
+	// EdgeRole holds the string denoting the role edge name in mutations.
+	EdgeRole = "role"
+	// EdgePermission holds the string denoting the permission edge name in mutations.
+	EdgePermission = "permission"
+	// Table holds the table name of the rolepermission in the database.
+	Table = "role_permissions"
+	// RoleTable is the table that holds the role relation/edge.
+	RoleTable = "role_permissions"
+	// RoleInverseTable is the table name for the Role entity.
+	// It exists in this package in order to avoid circular dependency with the "role" package.
+	RoleInverseTable = "roles"
+	// RoleColumn is the table column denoting the role relation/edge.
+	RoleColumn = "role_id"
+	// PermissionTable is the table that holds the permission relation/edge.
+	PermissionTable = "role_permissions"
+	// PermissionInverseTable is the table name for the Permission entity.
+	// It exists in this package in order to avoid circular dependency with the "permission" package.
+	PermissionInverseTable = "permissions"
+	// PermissionColumn is the table column denoting the permission relation/edge.
+	PermissionColumn = "permission_id"
+)
+
+// Columns holds all SQL columns for rolepermission fields.
+var Columns = []string{
+	FieldID,
+	FieldRoleID,
+	FieldPermissionID,
+}
+
+// ForeignKeys holds the SQL foreign-keys that are owned by the "role_permissions"
+// table and are not defined as standalone fields in the schema.
+var ForeignKeys = []string{
+	"permission_role_permissions",
+	"role_role_permissions",
+}
+
+// ValidColumn reports if the column name is valid (part of the table columns).
+func ValidColumn(column string) bool {
+	for i := range Columns {
+		if column == Columns[i] {
+			return true
+		}
+	}
+	for i := range ForeignKeys {
+		if column == ForeignKeys[i] {
+			return true
+		}
+	}
+	return false
+}
+
+// OrderOption defines the ordering options for the RolePermission queries.
+type OrderOption func(*sql.Selector)
+
+// ByID orders the results by the id field.
+func ByID(opts ...sql.OrderTermOption) OrderOption {
+	return sql.OrderByField(FieldID, opts...).ToFunc()
+}
+
+// ByRoleID orders the results by the role_id field.
+func ByRoleID(opts ...sql.OrderTermOption) OrderOption {
+	return sql.OrderByField(FieldRoleID, opts...).ToFunc()
+}
+
+// ByPermissionID orders the results by the permission_id field.
+func ByPermissionID(opts ...sql.OrderTermOption) OrderOption {
+	return sql.OrderByField(FieldPermissionID, opts...).ToFunc()
+}
+
+// ByRoleField orders the results by role field.
+func ByRoleField(field string, opts ...sql.OrderTermOption) OrderOption {
+	return func(s *sql.Selector) {
+		sqlgraph.OrderByNeighborTerms(s, newRoleStep(), sql.OrderByField(field, opts...))
+	}
+}
+
+// ByPermissionField orders the results by permission field.
+func ByPermissionField(field string, opts ...sql.OrderTermOption) OrderOption {
+	return func(s *sql.Selector) {
+		sqlgraph.OrderByNeighborTerms(s, newPermissionStep(), sql.OrderByField(field, opts...))
+	}
+}
+func newRoleStep() *sqlgraph.Step {
+	return sqlgraph.NewStep(
+		sqlgraph.From(Table, FieldID),
+		sqlgraph.To(RoleInverseTable, FieldID),
+		sqlgraph.Edge(sqlgraph.M2O, false, RoleTable, RoleColumn),
+	)
+}
+func newPermissionStep() *sqlgraph.Step {
+	return sqlgraph.NewStep(
+		sqlgraph.From(Table, FieldID),
+		sqlgraph.To(PermissionInverseTable, FieldID),
+		sqlgraph.Edge(sqlgraph.M2O, false, PermissionTable, PermissionColumn),
+	)
+}