UI: activity client links, online badges, ended-leases toggle, All activity

- Activity: a client's MAC address opens its leases; "Only this" filters
  the list to that client.
- Reservations: Online is a green online / grey offline badge.
- A subnet's leases: "Include ended leases" is a checkbox.
- Dashboard: "All activity" is a button beside the heading.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/web/static/assets/pages/activity.js

@@ -20,7 +20,9 @@ export async function render(el, params, query) {
           h("td", { class: "mono small" }, new Date(e.time).toLocaleTimeString(undefined, { hourCycle: "h23" })),
           h("td", { class: "mono" }, e.interface),
           h("td", null, h("strong", { class: "type-" + t.split(" ")[0] }, t)),
-          h("td", { class: "mono" }, e.mac ? h("a", { href: "#", onclick: (ev) => { ev.preventDefault(); mac.value = e.mac; draw(); } }, e.mac) : ""),
+          h("td", { class: "mono nowrap" }, e.mac ? [
+            h("a", { href: "#/leases?q=" + encodeURIComponent(e.mac), title: "This client's leases" }, e.mac), " ",
+            mac.value.trim() ? null : h("button", { class: "small reveal", title: "Show only this client's messages", onclick: () => { mac.value = e.mac; draw(); } }, "Only this")] : ""),
           h("td", { class: "mono" }, e.ip || ""),
           h("td", null, e.hostname || ""),
           h("td", { class: "detail" }, e.detail || ""));
@@ -30,7 +32,7 @@ export async function render(el, params, query) {
   iface.addEventListener("change", draw);
   mount(el,
     h("div", { class: "page-head" }, h("div", { class: "grow" }, h("h1", null, "Activity"),
-      h("div", { class: "muted" }, "The latest DHCP messages Steward received and sent, newest first. Click a MAC address to follow one client."))),
+      h("div", { class: "muted" }, "The latest DHCP messages Steward received and sent, newest first. A MAC address leads to that client's leases; Only this follows just that client."))),
     h("div", { class: "filter-row" }, mac, iface, pause),
     h("div", { class: "panel" }, out));
   await draw();