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/api/src/models/mod.rs

@@ -0,0 +1,3 @@
+mod response;
+
+pub use response::{ApiErrorResponse, ParamsErrorResponse, ValidationErrorResponse};

thoughts-backend/api/src/models/response.rs

@@ -0,0 +1,27 @@
+use std::collections::HashMap;
+
+use serde::Serialize;
+use utoipa::ToSchema;
+
+#[derive(Serialize, ToSchema)]
+pub struct ApiErrorResponse {
+    pub message: String,
+}
+
+#[derive(Serialize, ToSchema)]
+pub struct ValidationErrorResponse<T> {
+    pub message: String,
+    pub details: T,
+}
+
+pub type ParamsErrorResponse =
+    ValidationErrorResponse<HashMap<String, Vec<HashMap<String, String>>>>;
+
+impl<T> From<T> for ValidationErrorResponse<T> {
+    fn from(t: T) -> Self {
+        Self {
+            message: "Validation error".to_string(),
+            details: t,
+        }
+    }
+}