feat: add documentation crate and integrate OpenAPI specifications

- Added a new crate `doc` for API documentation.
- Integrated `utoipa` for OpenAPI support in the presentation layer.
- Updated routes to include social features (follow, unfollow, etc.) and diary export.
- Enhanced API request and response structures with new DTOs for social interactions.
- Updated `Cargo.toml` files to include new dependencies and features.
- Modified Dockerfile to copy the new documentation crate.
- Refactored existing handlers and routes to accommodate new API endpoints.
- Updated tests to cover new functionality and ensure proper API behavior.

crates/presentation/src/routes.rs

@@ -176,6 +176,13 @@ fn api_routes(rate_limit: u64) -> Router<AppState> {
             .route("/auth/login", routing::post(handlers::api::login))
             .route("/auth/register", routing::post(handlers::api::register))
             .route("/diary/export", routing::get(handlers::api::export_diary))
+            .route("/social/following", routing::get(handlers::api::get_following))
+            .route("/social/followers", routing::get(handlers::api::get_followers))
+            .route("/social/follow", routing::post(handlers::api::follow))
+            .route("/social/unfollow", routing::post(handlers::api::unfollow))
+            .route("/social/followers/accept", routing::post(handlers::api::accept_follower))
+            .route("/social/followers/reject", routing::post(handlers::api::reject_follower))
+            .route("/social/followers/remove", routing::post(handlers::api::remove_follower))
             .route_layer(auth_rate_limit),
     )
 }