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/components/layout/Sidebar.tsx

@@ -0,0 +1,71 @@
+import { NavLink } from "react-router-dom";
+import type { ComponentType, SVGProps } from "react";
+import {
+  CodesIcon,
+  MachinesIcon,
+  SessionsIcon,
+  UsersIcon,
+} from "./icons";
+
+interface NavItem {
+  to: string;
+  label: string;
+  Icon: ComponentType<SVGProps<SVGSVGElement>>;
+  /** Pass-1 stubs are disabled until their views land in later passes. */
+  enabled: boolean;
+}
+
+const NAV: NavItem[] = [
+  { to: "/machines", label: "Machines", Icon: MachinesIcon, enabled: true },
+  { to: "/sessions", label: "Sessions", Icon: SessionsIcon, enabled: false },
+  { to: "/codes", label: "Codes", Icon: CodesIcon, enabled: false },
+  { to: "/users", label: "Users", Icon: UsersIcon, enabled: false },
+];
+
+export function Sidebar() {
+  return (
+    <aside className="sidebar">
+      <div className="sidebar__brand">
+        <span className="sidebar__logo" aria-hidden="true">
+          GC
+        </span>
+        <span className="sidebar__name">
+          GuruConnect
+          <small>Operator Console</small>
+        </span>
+      </div>
+      <nav className="sidebar__nav" aria-label="Primary">
+        <span className="sidebar__section">Operations</span>
+        {NAV.map(({ to, label, Icon, enabled }) =>
+          enabled ? (
+            <NavLink
+              key={to}
+              to={to}
+              className={({ isActive }) =>
+                `navlink${isActive ? " navlink--active" : ""}`
+              }
+            >
+              <span className="navlink__icon">
+                <Icon />
+              </span>
+              {label}
+            </NavLink>
+          ) : (
+            <span
+              key={to}
+              className="navlink navlink--disabled"
+              aria-disabled="true"
+              title={`${label} — coming in a later pass`}
+            >
+              <span className="navlink__icon">
+                <Icon />
+              </span>
+              {label}
+              <span className="navlink__soon">Soon</span>
+            </span>
+          ),
+        )}
+      </nav>
+    </aside>
+  );
+}