Document hero panel arc; sync Dashboard Throughput chip to the hero's refresh cadence

ROADMAP.md

@@ -198,3 +198,5 @@ Roughly in priority order:
 `v0.16.35` unifies the Dashboard's Runtime/System panel with the Administration > System tab's hero panel instead of the two showing different, disagreeing numbers for the same underlying stats. The Dashboard's Memory tile used to read `process.memoryUsage().rss` -- the Node process's own footprint, not the container's real usage -- while the System tab's hero (added in v0.16.29-34) correctly read cgroup v2's `memory.current`. There was no CPU stat on the Dashboard at all, and "Site Gateway data" plus "Storage available" were two separate numbers where the System tab's Disk stat already combined them into one coherent, `DATA_DIR_LIMIT_GB`-aware percentage. Rather than keep two implementations in sync by hand, the Dashboard's panel is now the exact same hero component -- same markup builder, same `renderHeroPanel()` function, same `/api/system/health` endpoint, same polling-while-visible pattern -- so the two can't disagree again, because there's only one implementation computing the numbers. The Dashboard's copy shows CPU, Memory, Swap, Disk, Network, and Uptime; Throughput is left out there since the Dashboard already has its own "requests / min" chip in its metric strip and showing the same number twice added nothing. Uptime keeps ticking client-side exactly as it did before (same `updateDashboardUptime()` timer, just now living inside the hero's sixth slot instead of a standalone tile). Everything else that used to live in that panel -- Site Gateway version, Caddy version, Database status, and Public IP -- moved to the Administration > System tab's existing Version panel, alongside the Site Gateway version and access-URL details already shown there, so nothing was lost, it just now lives with the rest of the deployment's operational metadata instead of being split across two pages. The Dashboard's hero grid also gets its own CSS breakpoint (3 columns by default, 2 below 900px) rather than reusing the System tab's viewport-keyed breakpoints, since it sits inside the Dashboard's half-width two-column layout rather than a full-width panel and would otherwise stay cramped at 6 columns on an ordinary desktop window.
 
 `v0.16.36` opens `/api/system/health` up to every signed-in user instead of administrators only, so the Dashboard's hero panel (unified with the System tab's in v0.16.35) actually populates for standard users instead of sitting on dashes forever. It's a read-only endpoint with nothing destructive or sensitive behind it -- live CPU/memory/swap/disk/network numbers a standard user could already roughly infer from the Dashboard running fast or slow -- so it now follows the same no-admin-gate pattern as `/api/dashboard` rather than the stricter pattern used by the rest of `/api/system/*` (storage breakdown, restart, restart-policy), which stay administrator-only since those are either configuration detail or capable of restarting the container. Worth keeping in mind: when `DATA_DIR_LIMIT_GB` is set, each poll of this endpoint does a real recursive walk of `/data` to compute Site Gateway's own footprint (see v0.16.32) -- with multiple people viewing the Dashboard at once, each on their own 7-second timer, that's now multiple concurrent walks instead of one administrator's. Not a problem at ordinary usage levels, but worth revisiting (e.g. a shared, briefly-cached snapshot) if it's ever noticeably heavy with a lot of concurrent viewers.
+
+`v0.16.37` combines the documentation catch-up for the hero panel arc (v0.16.29-36: README feature bullets and the environment-variable table, plus new "Live resource panel" and "Version" sections in the in-app manual's Administration System article, and an updated Dashboard "Runtime & System" article) with a real fix found while reviewing the Dashboard's hero panel live: the Throughput chip next to it (requests/min) was still only updating on the old 30-second `refreshDashboard()` timer, not the hero's 7-second poll, even though `/api/system/health` already computes that exact number on every call and the Dashboard was just discarding it. `refreshDashboardHero()` now also updates the Throughput chip from that same response, so it refreshes on the same cadence as the rest of the hero instead of lagging behind it by up to 23 seconds.