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.

config/services.php

@@ -40,6 +40,12 @@ return [
         'jwt_algorithm' => env('FASTAPI_AGENT_JWT_ALGORITHM', 'HS256'),
     ],
 
+    'bnfexpress' => [
+        'ai_api_url' => env('BNFEXPRESS_AI_API_URL', 'http://bnfexpress-app:8000'),
+        'client_id' => env('BNFEXPRESS_AI_CLIENT_ID', 'ev_admin'),
+        'client_secret' => env('BNFEXPRESS_AI_CLIENT_SECRET'),
+    ],
+
     'sms' => [
         'enabled' => env('SMS_ENABLED', false),
         'sms_poh' => [