Finish report-output loading, breadcrumb, and Plotly isolation fixes

Most of the original report-output action and navigation work is now implemented: shared reports expose safe actions, setup is read-only for shared sources, and navigation uses canonical report paths.

The remaining code-level defects are:

• Setup and report-output routes still render blocking Loading report... states instead of using available cached data immediately.
• The reproduce breadcrumb derives its label from the report name or ID, producing Back to [report] instead of Back to report output.
• SocietyWideOverview still imports react-plotly.js statically in a module rendered by a Next route; isolate Plotly behind a client-only dynamic boundary so server rendering does not evaluate it.

Update focused tests for each remaining behavior.

Start with the setup and report-output routes, the reproduce breadcrumb, and SocietyWideOverview, then inspect their focused tests. Verify cached data renders without blocking loading states, the breadcrumb says “Back to report output,” and Plotly is isolated behind a client-only boundary so the Next route can server-render safely.