feat(dashboard): GuruConnect v2 operator console (pass 1)

React + Vite + TypeScript SPA: scaffold, operations-terminal design
system, Bearer-token auth, and the Machines view.

- Design system: OKLCH-tinted dark theme (ink-slate + signal-cyan),
  Hanken Grotesk + JetBrains Mono, status-color language
  (online/offline/granted/pending/denied/not_required), motion with
  prefers-reduced-motion honored.
- Auth: token in sessionStorage via ref (never React state), protected
  routes, 401 session teardown, admin-gated per-agent-key UI.
- Machines view: data table (sticky header, keyboard-activated rows,
  skeleton loading, actionable empty/error states), non-blocking detail
  drawer, delete confirm, admin key management with copy-once reveal.
- UI primitives: Modal (focus trap + inert + portal + dialogStack),
  Drawer, Table, Badge/StatusDot, toast, states.
- Typed API client normalizing the two error-envelope shapes.

Passed Code Review (no blockers), impeccable critique-and-polish, and
local gates (tsc/lint/build green). Dev-only Vite proxy to :3002.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

dashboard/src/lib/time.ts

@@ -0,0 +1,60 @@
+// Time formatting helpers. Relative for at-a-glance scanning, absolute (mono)
+// for the precise value on hover.
+
+const UNITS: [Intl.RelativeTimeFormatUnit, number][] = [
+  ["year", 60 * 60 * 24 * 365],
+  ["month", 60 * 60 * 24 * 30],
+  ["day", 60 * 60 * 24],
+  ["hour", 60 * 60],
+  ["minute", 60],
+  ["second", 1],
+];
+
+const rtf = new Intl.RelativeTimeFormat(undefined, { numeric: "auto" });
+
+/**
+ * Human relative time, e.g. "3 minutes ago" / "in 2 days". Returns "—" for
+ * missing input and "just now" for sub-10-second deltas.
+ */
+export function relativeTime(iso: string | null | undefined): string {
+  if (!iso) return "—";
+  const then = new Date(iso).getTime();
+  if (Number.isNaN(then)) return "—";
+
+  const deltaSec = Math.round((then - Date.now()) / 1000);
+  const abs = Math.abs(deltaSec);
+  if (abs < 10) return "just now";
+
+  for (const [unit, secs] of UNITS) {
+    if (abs >= secs || unit === "second") {
+      return rtf.format(Math.round(deltaSec / secs), unit);
+    }
+  }
+  return "just now";
+}
+
+/** Absolute local timestamp for tooltips / mono display. */
+export function absoluteTime(iso: string | null | undefined): string {
+  if (!iso) return "—";
+  const d = new Date(iso);
+  if (Number.isNaN(d.getTime())) return "—";
+  return d.toLocaleString(undefined, {
+    year: "numeric",
+    month: "short",
+    day: "2-digit",
+    hour: "2-digit",
+    minute: "2-digit",
+    second: "2-digit",
+  });
+}
+
+/** Format a duration in seconds as a compact "1h 04m" / "47s" string. */
+export function formatDuration(secs: number | null | undefined): string {
+  if (secs == null || secs < 0) return "—";
+  const h = Math.floor(secs / 3600);
+  const m = Math.floor((secs % 3600) / 60);
+  const s = secs % 60;
+  if (h > 0) return `${h}h ${String(m).padStart(2, "0")}m`;
+  if (m > 0) return `${m}m ${String(s).padStart(2, "0")}s`;
+  return `${s}s`;
+}