refactor: purge Node.js, Rust is the one true backend

- Moved boosapi-rs/* to repo root
- Deleted all Node.js source (src/server/, src/web/, scripts/)
- Deleted node_modules, package.json, tsconfig, vite.config
- Updated .gitignore and AGENTS.md for Rust-only stack
- Fixed static file path for frontend dist/web/
- Dockerfile stays the same (already Rust-only)
- Kept dist/web/ for Rust static serving

src/web/pages/tokens.redirect.test.tsx

@@ -1,48 +0,0 @@
-import { describe, expect, it, vi } from 'vitest';
-import { act, create } from 'react-test-renderer';
-import { MemoryRouter, Route, Routes, useLocation } from 'react-router-dom';
-import { ToastProvider } from '../components/Toast.js';
-import Tokens from './Tokens.js';
-
-const { apiMock } = vi.hoisted(() => ({
-  apiMock: {
-    getAccountTokens: vi.fn().mockResolvedValue([]),
-    getAccounts: vi.fn().mockResolvedValue([]),
-    getAccountTokenGroups: vi.fn().mockResolvedValue({ groups: ['default'] }),
-  },
-}));
-
-vi.mock('../api.js', () => ({
-  api: apiMock,
-}));
-
-function LocationProbe() {
-  const location = useLocation();
-  return <div>{`${location.pathname}${location.search}`}</div>;
-}
-
-describe('Tokens legacy route redirect', () => {
-  it('redirects /tokens to the merged accounts tokens segment', async () => {
-    let root!: WebTestRenderer;
-    await act(async () => {
-      root = create(
-        <ToastProvider>
-          <MemoryRouter initialEntries={['/tokens?create=1&accountId=23&model=gpt-4.1']}>
-            <Routes>
-              <Route path="/tokens" element={<Tokens />} />
-              <Route path="/accounts" element={<LocationProbe />} />
-            </Routes>
-          </MemoryRouter>
-        </ToastProvider>,
-      );
-    });
-
-    const rendered = JSON.stringify(root?.toJSON());
-    expect(rendered).toContain('/accounts?');
-    expect(rendered).toContain('segment=tokens');
-    expect(rendered).toContain('create=1');
-    expect(rendered).toContain('accountId=23');
-    expect(rendered).toContain('model=gpt-4.1');
-    root?.unmount();
-  });
-});