Synced study — reduced startup refusal

Owner-feedback revision. Sidebar metrics, warning SF Symbol and 360pt/content-height popover are reused from the existing mockups. Main panes reuse the native unavailable-pane layout with the cause as the heading. This mockup does not activate or change the app.

• Known origin: the sidebar keeps “Started on another Mac”. Main pane and popover share the cause, available friendly Mac name/start time, then a separate consequence paragraph.
• Only the friendly Apple display name is shown. If unavailable, use “another Mac”; never substitute a DNS hostname. Omit unknown time. The metadata selector is a review control outside the app.
• Unverified origin: “Activity not confirmed”. No guessed name or start time. Main pane and popover share the same explanation.
• Retry remains the only action in both main panes, including repeated refusals. It checks the evidence again, never overrides protection. Nothing changes if the evidence is unchanged. There is no automatic eventual unlock promise.
• No Show details, Hide details or Send Feedback action in these panes. Copy details remains in the popover and copies the diagnostic record for troubleshooting.
• The study cannot be viewed or edited here while startup is refused. Read-only browsing stays in 100days for later. No cartouche, takeover, duplicate or unlock control.
• A recorded terminus can remove this particular refusal on a new check; it does not prove a complete synced study or shared SQLite safety. Newly arrived activity while a window is already open remains outside this startup protection.