Replaced manual login and context loading across tests with Playwright's `test.use` configuration for user authentication. This simplifies test setup, improves readability, and reduces repetition. For #6362 Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/6400 Reviewed-by: Gusted <gusted@noreply.codeberg.org> Co-authored-by: Julian Schlarb <julian.schlarb@denktmit.de> Co-committed-by: Julian Schlarb <julian.schlarb@denktmit.de>