feat: initialize thoughts-frontend with Next.js, TypeScript, and ESLint

- Add ESLint configuration for Next.js and TypeScript support.
- Create Next.js configuration file with standalone output option.
- Initialize package.json with scripts for development, build, and linting.
- Set up PostCSS configuration for Tailwind CSS.
- Add SVG assets for UI components.
- Create TypeScript configuration for strict type checking and module resolution.

thoughts-backend/tests/app/persistence/user.rs

@@ -0,0 +1,18 @@
+use sea_orm::{DatabaseConnection, Unchanged};
+
+use app::persistence::user::create_user;
+use models::domains::user;
+use models::params::user::CreateUserParams;
+
+pub(super) async fn test_user(db: &DatabaseConnection) {
+    let params = CreateUserParams {
+        username: "test".to_string(),
+    };
+
+    let user = create_user(db, params).await.expect("Create user failed!");
+    let expected = user::ActiveModel {
+        id: Unchanged(1),
+        username: Unchanged("test".to_owned()),
+    };
+    assert_eq!(user, expected);
+}