feat: UI separates locals, remotes, and virtuals (#54)

## Summary
- New "Locals" sidebar nav item with list + detail + browse pages
- Remotes page filters out local repos (repo_type=local hidden)
- LocalDetail: simplified view — just name, type, description + "Browse Files" button
- Virtuals: member links resolve to /locals/ or /remotes/ based on repo_type
- Objects page detects context for correct back-navigation

## Test plan
- [ ] Visual check: locals page shows only local repos
- [ ] Remotes page hides local repos
- [ ] Virtual member links point to correct pages
- [ ] Browse files works from local detail page

Reviewed-on: #54
Co-authored-by: Ben Vincent <ben@unkin.net>
Co-committed-by: Ben Vincent <ben@unkin.net>

ui/src/pages/LocalDetail.tsx

@@ -0,0 +1,46 @@
+import { useEffect, useState } from 'react';
+import { useParams, Link } from 'react-router-dom';
+import { api } from '../api/client';
+import type { Remote } from '../api/types';
+import { Badge } from '../components/Badge';
+import './RemoteDetail.css';
+
+export function LocalDetail() {
+  const { name } = useParams<{ name: string }>();
+  const [remote, setRemote] = useState<Remote | null>(null);
+  const [error, setError] = useState<string | null>(null);
+
+  useEffect(() => {
+    if (!name) return;
+    api.getRemote(name)
+      .then(setRemote)
+      .catch(e => setError(e.message));
+  }, [name]);
+
+  if (error) return <div className="error-banner">{error}</div>;
+  if (!remote) return <div className="loading">Loading...</div>;
+
+  return (
+    <div>
+      <div className="detail-header">
+        <Link to="/locals" className="back-link">&larr; Locals</Link>
+        <h1 className="page-title">{remote.name}</h1>
+        <div className="detail-badges">
+          <Badge variant="blue">{remote.package_type}</Badge>
+          <Badge variant="default">local</Badge>
+          {remote.managed_by && <Badge variant="green">managed by {remote.managed_by}</Badge>}
+        </div>
+      </div>
+
+      {remote.description && (
+        <p className="detail-description">{remote.description}</p>
+      )}
+
+      <div className="detail-actions">
+        <Link to={`/locals/${remote.name}/objects`} className="btn btn-primary">
+          Browse Files
+        </Link>
+      </div>
+    </div>
+  );
+}