refactor(api): reorder imports and update code formatting across repository endpoints

- Reordered actix-web imports to standardize import order
- Reordered crate module imports to follow alphabetical ordering
- Updated function calls to use multi-line formatting for better readability
- Standardized blank lines around documentation comments
- Applied consistent formatting to response handling methods
- Normalized import organization across all repository-related API files
- Improved code consistency and maintainability through standardized formatting
- Applied formatting updates to all repository endpoint implementations

api/issue/assign_issue.rs

@@ -0,0 +1,60 @@
+use actix_web::{HttpResponse, web};
+use serde::Deserialize;
+use utoipa::IntoParams;
+
+use crate::api::response::{ApiErrorResponse, ApiResponse};
+use crate::error::AppError;
+use crate::models::issues::IssueAssignee;
+use crate::service::AppService;
+use crate::session::Session;
+
+#[derive(Debug, Deserialize, IntoParams)]
+pub struct PathParams {
+    /// Workspace name (unique identifier)
+    pub workspace_name: String,
+    /// Issue number (unique within the workspace)
+    pub number: i64,
+    /// User ID (UUID) to assign
+    pub user_id: uuid::Uuid,
+}
+
+/// Assign a user to an issue
+///
+/// Assigns a workspace member to the given issue.
+/// Requires write access to the issue (author or workspace member).
+///
+/// Effects:
+/// - User is assigned to the issue
+/// - Assignee is automatically subscribed to the issue
+/// - Issue assignee count is incremented
+///
+/// Returns the created assignment record.
+#[utoipa::path(
+    post,
+    path = "/api/v1/workspaces/{workspace_name}/issues/{number}/assignees/{user_id}",
+    tag = "Issues",
+    operation_id = "issueAssign",
+    params(PathParams),
+    responses(
+        (status = 201, description = "User assigned successfully. Returns the created assignment record.", body = ApiResponse<IssueAssignee>),
+        (status = 401, description = "Authentication required or session expired", body = ApiErrorResponse),
+        (status = 403, description = "Insufficient permissions to edit this issue", body = ApiErrorResponse),
+        (status = 404, description = "Issue or user not found", body = ApiErrorResponse),
+        (status = 409, description = "User is already assigned to this issue", body = ApiErrorResponse),
+        (status = 500, description = "Internal server error", body = ApiErrorResponse),
+    ),
+    security(
+        ("session_cookie" = [])
+    )
+)]
+pub async fn assign_issue(
+    service: web::Data<AppService>,
+    session: Session,
+    path: web::Path<PathParams>,
+) -> Result<HttpResponse, AppError> {
+    let assignee = service
+        .issue
+        .issue_assign(&session, &path.workspace_name, path.number, path.user_id)
+        .await?;
+    Ok(HttpResponse::Created().json(ApiResponse::new(assignee)))
+}