docs(skills): 添加 Better Auth 最佳实践与安全配置指南

drizzle/20260717073616_milky_calypso/migration.sql

@@ -0,0 +1,13 @@
+CREATE TABLE "upload" (
+	"id" text PRIMARY KEY,
+	"original_name" text NOT NULL,
+	"oss_key" text NOT NULL UNIQUE,
+	"url" text NOT NULL,
+	"mime_type" text NOT NULL,
+	"size" integer NOT NULL,
+	"bucket" text NOT NULL,
+	"user_id" text,
+	"created_at" timestamp with time zone DEFAULT now() NOT NULL
+);
+--> statement-breakpoint
+ALTER TABLE "upload" ADD CONSTRAINT "upload_user_id_user_id_fkey" FOREIGN KEY ("user_id") REFERENCES "user"("id") ON DELETE SET NULL;