Merge main: the collaboration screens under the redesigned shell master
The redesign moved the repository heading, the section tabs and the clone menu into the app shell. Every screen below it holds the window and scrolls inside itself. The collaboration screens take that shape here. Work, Issues and Change join the section band. RepoTabs names Work only where the config names contributors, the way it names Checks only where a runner is named. The source view drops the Issues and Work buttons it carried, because the band above reaches both. A commit reads as two panes. The review composer, the conversation and the line comments read down the right one with the diffs. Breadcrumbs drop the repository crumb the heading carries, and keep the `trail` a change's commit list needs. The diff gutter is cut to the file's widest line number, so the comment button sits at the seam rather than at a fixed offset. Two columns of numbers become one on a narrow window, and the button follows. checkRunnerFor and repoRunner answered the same question. repoRunner keeps its answer once read, so collab.js reads it too. The header carries the visitor's session beside the palette and the account being browsed. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01RomHvaB4nyAckbRD7W36Ue