web: server-screen, footer, monitoring-sidebar, and responsive-header polish #1682

Server-screen, footer, monitoring-sidebar, and responsive-header polish, grouped under one issue.

• Connected server card — on a successful connect, highlight the card (green border) and scroll it into view once the monitoring sidebar has opened, mirroring the errored-card path (Open the monitoring sidebar on connection failure, with a Console (stderr) tab for stdio servers #1621).
• Failed status — the connection indicator shows a red dot + "Failed" when a connect attempt fails, instead of the grey "Disconnected" it settles back to.
• Footer row — move the version + copyright out of the fixed bottom-corner badges into a real full-width AppShell.Footer (header-matching background + top border) so the monitoring sidebar no longer cuts through them.
• MCP-docs tooltip — add an "MCP Documentation" tooltip to the MCP logo link.
• Servers box — wrap the Servers screen in a bordered, container-filling box (like the Messages panel), "Servers" title on the left and Export / Add Servers / collapse on the right; the card grid scrolls inside.
• Card-surface refresh — give the server cards and the Protocol/Network/Task entry cards a faint gray-0 fill (lighter than the grey app background) with white raised code blocks.
• Monitoring-sidebar layout — drop the divider between the controls and content, align the tab/search controls to the content-panel width, add a small top margin, and halve the controls→content gap.
• Responsive layout (1280px floor) — add a 1280px app min-width that the whole app (header included) honors, scrolling horizontally below it. Simplify the header: Disconnect is always a grey icon (with a "Disconnect from server" tooltip), tabs are always a SegmentedControl, and the connection status text drops below 1500px. Remove the 1040px gate on the monitoring sidebar so it's available whenever a server is connected/failed and a monitor tab exists.
• Compact Protocol entry — a long resource URI scrolls horizontally in its own area instead of truncating with an ellipsis (mirroring the Network entry's URL).
• Copy buttons — add a copy button beside resource URIs in the Protocol entry and the request URL in the Network entry, so URLs can be copied easily.