refactor(workspace): pass workspace object instead of id to service methods

- Replace workspace_id parameter with Workspace object reference in all workspace service methods
- Remove redundant find_workspace_by_id calls that were duplicated in each method
- Update all method signatures across approval, audit, billing, branding, core, settings and stats modules
- Modify SQL queries to bind ws.id instead of separate workspace_id parameter
- Add Workspace import to all affected modules
- Adjust method calls in API handlers to pass workspace object instead of id
- Consolidate workspace retrieval logic to single location per operation flow

api/workspace/revoke_invitation.rs

@@ -0,0 +1,39 @@
+use actix_web::{HttpResponse, web};
+use uuid::Uuid;
+
+use crate::api::response::{ApiEmptyResponse, ApiErrorResponse};
+use crate::error::AppError;
+use crate::service::AppService;
+use crate::session::Session;
+
+#[utoipa::path(
+    delete,
+    path = "/api/v1/workspaces/{workspace_name}/invitations/{invitation_id}",
+    tag = "Workspaces",
+    operation_id = "workspaceRevokeInvitation",
+    summary = "Revoke an invitation",
+    description = "Revoke a pending invitation so it can no longer be accepted. Requires admin role.",
+    params(
+        ("workspace_name" = String, Path, description = "Workspace name."),
+        ("invitation_id" = Uuid, Path, description = "Invitation ID.")
+    ),
+    responses(
+        (status = 200, description = "Invitation revoked.", body = ApiEmptyResponse),
+        (status = 401, description = "Unauthenticated or insufficient role.", body = ApiErrorResponse),
+        (status = 404, description = "Invitation not found or already used.", body = ApiErrorResponse),
+        (status = 500, description = "Database transaction failed.", body = ApiErrorResponse)
+    )
+)]
+pub async fn handle(
+    service: web::Data<AppService>,
+    session: Session,
+    path: web::Path<(String, Uuid)>,
+) -> Result<HttpResponse, AppError> {
+    let (ws_name, invitation_id) = path.into_inner();
+    let ws = service.workspace.find_workspace_by_name(&ws_name).await?;
+    service
+        .workspace
+        .workspace_revoke_invitation(&session, &ws, invitation_id)
+        .await?;
+    Ok(HttpResponse::Ok().json(ApiEmptyResponse::ok("invitation revoked")))
+}