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/features/auth/LoginPage.tsx

@@ -0,0 +1,106 @@
+import { useState } from "react";
+import { Navigate, useLocation, useNavigate } from "react-router-dom";
+import { ApiError } from "../../api/client";
+import { useAuth } from "../../auth/AuthContext";
+import { Button } from "../../components/ui/Button";
+import { Field, Input } from "../../components/ui/Input";
+import "./login.css";
+
+interface LocationState {
+  from?: { pathname: string };
+}
+
+export function LoginPage() {
+  const { user, login } = useAuth();
+  const navigate = useNavigate();
+  const location = useLocation();
+
+  const [username, setUsername] = useState("");
+  const [password, setPassword] = useState("");
+  const [error, setError] = useState<string | null>(null);
+  const [submitting, setSubmitting] = useState(false);
+
+  // Already authenticated — bounce to the app.
+  if (user) return <Navigate to="/machines" replace />;
+
+  const from = (location.state as LocationState | null)?.from?.pathname ?? "/machines";
+
+  async function handleSubmit(e: React.FormEvent) {
+    e.preventDefault();
+    setError(null);
+    setSubmitting(true);
+    try {
+      await login(username, password);
+      navigate(from, { replace: true });
+    } catch (err) {
+      if (err instanceof ApiError) {
+        setError(
+          err.status === 401
+            ? "Invalid username or password."
+            : err.message,
+        );
+      } else {
+        setError("Could not sign in. Please try again.");
+      }
+    } finally {
+      setSubmitting(false);
+    }
+  }
+
+  return (
+    <div className="login">
+      <div className="login__scanlines" aria-hidden="true" />
+      <form className="login__card" onSubmit={handleSubmit}>
+        <div className="login__brand">
+          <span className="login__logo" aria-hidden="true">
+            GC
+          </span>
+          <div>
+            <div className="login__title">GuruConnect</div>
+            <div className="login__sub">Operator Console</div>
+          </div>
+        </div>
+
+        <Field label="Username" htmlFor="username">
+          <Input
+            id="username"
+            autoComplete="username"
+            value={username}
+            onChange={(e) => setUsername(e.target.value)}
+            autoFocus
+            required
+          />
+        </Field>
+
+        <Field label="Password" htmlFor="password">
+          <Input
+            id="password"
+            type="password"
+            autoComplete="current-password"
+            value={password}
+            onChange={(e) => setPassword(e.target.value)}
+            required
+          />
+        </Field>
+
+        {error && (
+          <div className="login__error" role="alert">
+            {error}
+          </div>
+        )}
+
+        <Button
+          type="submit"
+          variant="primary"
+          block
+          loading={submitting}
+          disabled={!username || !password}
+        >
+          Sign in
+        </Button>
+
+        <div className="login__foot mono">GuruConnect · Operator Console</div>
+      </form>
+    </div>
+  );
+}