feat: 接入 Database 三资源 API 与分层绑定协调

确定单库单账号、集群级 Database、资源侧先写绑定和凭据定位合同。领域层承载纯规则，service 协調流程，Kubernetes adapter 负责资源呈现与版本保护。

验证：全量 make test、三轮 race、真实 API server 并发与重启补写、最小 RBAC/watch、lint 和文档检查通过。供应、凭据交付及删除清理尚未实现，保留 DeletionPending/finalizer 边界。

internal/database/controller/binding_controller.go

@@ -0,0 +1,47 @@
+// Package controller 将 Database 用例接入 Kubernetes 事件和重试调度。
+package controller
+
+import (
+	"context"
+	"time"
+
+	"git.ddupan.top/panxiao81/ayatori/internal/database/adapter/kubernetes"
+	"git.ddupan.top/panxiao81/ayatori/internal/database/application"
+	ctrl "sigs.k8s.io/controller-runtime"
+	"sigs.k8s.io/controller-runtime/pkg/client"
+)
+
+const dependencyRetry = 30 * time.Second
+
+type BindingReconciler struct {
+	Client client.Client
+	Reader client.Reader
+}
+
+// +kubebuilder:rbac:groups=database.ayatori.ddupan.top,resources=postgresqltenants,verbs=get;list;watch;update;patch
+// +kubebuilder:rbac:groups=database.ayatori.ddupan.top,resources=postgresqltenants/status,verbs=get;update;patch
+// +kubebuilder:rbac:groups=database.ayatori.ddupan.top,resources=postgresqltenants/finalizers,verbs=update
+// +kubebuilder:rbac:groups=database.ayatori.ddupan.top,resources=postgresqldatabases,verbs=get;list;watch;create;update;patch
+// +kubebuilder:rbac:groups=database.ayatori.ddupan.top,resources=postgresqldatabases/status,verbs=get;update;patch
+// +kubebuilder:rbac:groups=database.ayatori.ddupan.top,resources=postgresqldatabases/finalizers,verbs=update
+// +kubebuilder:rbac:groups=database.ayatori.ddupan.top,resources=postgresqlinstances,verbs=get;list;watch
+
+func (r *BindingReconciler) Reconcile(ctx context.Context, request ctrl.Request) (ctrl.Result, error) {
+	resources := &kubernetes.BindingResources{Client: r.Client, Reader: r.Reader}
+	service := application.BindingService{Resources: resources}
+	result, err := service.Reconcile(ctx, request.Namespace, request.Name)
+	if err != nil {
+		return ctrl.Result{}, err
+	}
+	if err := resources.Present(ctx, result); err != nil {
+		return ctrl.Result{}, err
+	}
+	if result.RetrySoon {
+		return ctrl.Result{RequeueAfter: time.Millisecond}, nil
+	}
+	if result.Tenant == nil {
+		return ctrl.Result{}, nil
+	}
+	// watch 是主入口，低频重查覆盖依赖事件映射失败，不做冲突忙循环。
+	return ctrl.Result{RequeueAfter: dependencyRetry}, nil
+}