v1.57.3

Fixed

• Error toasts in the Web UI didn't look like errors. Eight of them passed 'error' to the toast helper, but the stylesheet only defines is-success / is-warn / is-danger — so is-error matched no rule and the toast came up in the neutral accent colour instead of red. A failed import or a network error read like a normal notice. They pass 'danger' now, which is the class the stylesheet actually has. (A second, dead copy of the toast function — the one that made 'error' look plausible in the first place, unreachable since the shared script loads — is removed.)
• The container detail page could show the wrong image's size. It inspected the tag reference for {{.Size}}, so if the tag had moved forward but the container wasn't recreated (the same #53 drift), it reported the new image's size rather than the one the container runs. It now inspects the running image ID, matching what the status table (v1.47.0) and the update check (v1.57.x) already do.