SUEZ, Egypt—A maritime traffic jam grew to more than 200 vessels Friday outside the Suez Canal and some vessels began changing course as dredgers worked frantically to free a giant container ship that is stuck sideways in the waterway and disrupting global shipping. One salvage expert said freeing the cargo ship, the Ever Given, could take up to a week in the best-case scenario and warned of possible structural problems on the vessel as it remains wedged. The Suez Canal Authority said it welcomed international offers to help free the vessel, including one from the United States, although it did not say what kind of assistance was offered. The Ever Given, owned by the Japanese firm Shoei Kisen KK, got wedged Tuesday in a single-lane stretch of the canal, about 6 kilometers (3.7 miles) north of the southern entrance, near the city of Suez. The vessel remained grounded Friday morning, …