Add urapt-web: web UI for urapt-server instances

A Vite + React 18 + TypeScript SPA, same-origin with the API (no CORS,
no Go server changes). Full management parity with the urapt CLI:

- First-run setup (admin bootstrap via needs_setup), login/logout
- Repositories: list, create, tabbed detail (overview edit/delete,
  members CRUD, distributions/components/architectures manager,
  package list + .deb upload + detail + delete, apt-config panel)
- API tokens: show-once creation + revoke
- Admin users: toggle admin / delete
- Settings + dark mode

Stack: Tailwind + shadcn/ui (New York), React Router v7 (lazy routes),
TanStack Query v5, Zustand, Vitest. Hand-written typed API client
mirroring shared/api + shared/models. Dev proxy forwards /api + /apt
to a local urapt-server; deploy behind nginx/Caddy (see urapt-web/README).

urapt-web/.gitignore

@@ -0,0 +1,35 @@
+# dependencies
+node_modules
+
+# build
+dist
+dist-ssr
+*.local
+*.tsbuildinfo
+
+# logs
+logs
+*.log
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+pnpm-debug.log*
+
+# editor / os
+.DS_Store
+.idea
+.vscode/*
+!.vscode/extensions.json
+*.suo
+*.ntvs*
+*.njsproj
+*.sln
+*.sw?
+
+# test
+coverage
+
+# env
+.env
+.env.*
+!.env.example