Add bnfexpress signed admin client and AI Agent Filament UI

- Modules\Shared\Bnfexpress\BnfexpressAdminClient: HMAC-signed HTTP client
  for bnfexpress's admin API (EV FAQs, agent instructions, chat history),
  with a bnfexpress:smoke-test command and full unit coverage.
- New ai-agent module: Filament pages to manage EV FAQs, publish/roll back
  agent instruction versions, and browse EV chat history + transcripts.
- New manage_ai_agent permission (super_admin/admin).
- Recorded .ai/rules for the client's auth scheme and non-Resource
  Filament page/table testing gotchas.

composer.json

@@ -14,6 +14,7 @@
         "laravel/sanctum": "^4.0",
         "laravel/tinker": "^3.0",
         "internachi/modular": "^3.0",
+        "modules/ai-agent": "*",
         "modules/booking": "*",
         "modules/catalog": "*",
         "modules/cms": "*",