Node Health tab on a phone: empty Metrics

Seen during Task 7239's visual check of the node detail Health tab (local stack, 448px, 2026-10-18). Suggestions: 1. The "Metrics" card with no samples spends ~120px on "No metrics reported yet" under its range picker. Collapse it to its title row (as Updates now does: "None recorded" on the header) and hide the 1h/6h/24h/7d picker until there is data to range over. 2. The "Disk" card reading only "No cleanups or pauses yet" takes a full card. Collapse it to its title row the same way (`SectionCard` with no children renders the header alone). 3. On a phone the node detail tab strip wraps to a second line ("MicroVM", "CI runners"); desktop uses a "More ▾" overflow. Use the same overflow below `sm`. Out of scope: what the metrics/disk data mean; the Verdict, Clocks and Updates cards. Done means: - A 448px screenshot of a never-connected node's Health tab shows Metrics and Disk as one-line rows and the tab strip on one line. - `./dc check quick` is green; the lane merges the PR.

Node Health tab on a phone: empty Metrics and Disk collapse to one title row (no range picker), node tabs stay on one line with More. Quick gate and e2e green; 448px visual check OK. PR #5896 merged (4389ef8); deploy superseded. Follow-up #7260 filed.