feat(phase-2): workstream 6 — Web Dashboard UI

- dashboard/: Vite 5 + React 18 + TypeScript strict SPA
  - Auth: sessionStorage credentials, TokenManager validation, AuthProvider context
  - Pages: Login, Agents (search + filter), AgentDetail (suspend/reactivate),
    Credentials (generate/rotate/revoke, new secret shown once),
    AuditLog (filters + pagination), Health (PG + Redis status, 30s refresh)
  - Components: Button, Badge, ConfirmDialog, AppShell, RequireAuth
  - All destructive actions gated by ConfirmDialog
  - Zero dangerouslySetInnerHTML; sessionStorage only (OWASP compliant)
- src/routes/health.ts: unauthenticated GET /health — PG + Redis connectivity
- src/app.ts: health route + dashboard/dist/ served at /dashboard with SPA fallback
- 6 new health route tests; 308/308 unit tests passing

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

dashboard/tailwind.config.js

@@ -0,0 +1,19 @@
+/** @type {import('tailwindcss').Config} */
+export default {
+  content: ['./index.html', './src/**/*.{ts,tsx}'],
+  theme: {
+    extend: {
+      colors: {
+        brand: {
+          50:  '#f0f9ff',
+          100: '#e0f2fe',
+          500: '#0ea5e9',
+          600: '#0284c7',
+          700: '#0369a1',
+          900: '#0c4a6e',
+        },
+      },
+    },
+  },
+  plugins: [],
+};