chore: import upstream snapshot with attribution

backend/tests/manual/test-users.sql

@@ -0,0 +1,18 @@
+-- Table: test_users2
+CREATE TABLE IF NOT EXISTS test_users (
+    id uuid PRIMARY KEY DEFAULT gen_random_uuid(),
+    nickname text,
+    avatar_url text,
+    birthday date,
+    extra jsonb,
+    created_at timestamp with time zone DEFAULT now(),
+    updated_at timestamp with time zone DEFAULT now()
+);
+
+CREATE POLICY "Enable read access for all users" ON test_users FOR SELECT TO public USING (true);
+CREATE POLICY "Enable update for users based on user_id" ON test_users FOR UPDATE TO authenticated USING ((uid() = id));
+
+-- Sample data for test_users
+INSERT INTO test_users (nickname, avatar_url, birthday) VALUES 
+('John Doe', 'https://example.com/avatar1.jpg', '1990-01-01'),
+('Jane Smith', 'https://example.com/avatar2.jpg', '1985-05-15');