Node Health tab: empty Metrics/Disk cards

Seen during Task 7260's visual check of the node detail Health tab (local stack, `dev-node` never connected, 448px and 1280px, 2026-10-18). Suggestions: 1. Metrics on a node with no samples still spends a ~120px card body on "No metrics reported yet"; collapse it to its title row (as Updates and Reporting clocks now do), keeping the range selector hidden or disabled while there is nothing to range over. 2. Disk with no events spends a ~120px body on "No cleanups or pauses yet"; collapse it to its title row with a short right-aligned "None yet". 3. At 448px the node detail tabs (Overview, Health, Properties, Projects, NodeLinks, MicroVM, CI runners) wrap onto two lines; use the "More ▾" overflow the 1280px pane already uses. Out of scope: what the verdicts and clocks mean; the Verdict, Reporting clocks and Updates cards. Done means: - A 448px screenshot of a never-connected node's Health tab shows Metrics and Disk as one row each and the tab strip on one line. - `./dc check quick` is green; the lane merges the PR.

Already shipped by Task 7247 (9de8ed876). A 448px screenshot of the never-connected dev-node shows Metrics and Disk as one row each and the tabs on one line with More ▾. No PR. Filed draft #7347 to fold the empty Health cards into one line.