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.

app-modules/ai-agent/composer.json

@@ -0,0 +1,24 @@
+{
+	"name": "modules/ai-agent",
+	"description": "",
+	"type": "library",
+	"version": "1.0",
+	"license": "proprietary",
+	"require": {},
+	"autoload": {
+		"psr-4": {
+			"Modules\\AiAgent\\": "src/",
+			"Modules\\AiAgent\\Tests\\": "tests/",
+			"Modules\\AiAgent\\Database\\Factories\\": "database/factories/",
+			"Modules\\AiAgent\\Database\\Seeders\\": "database/seeders/"
+		}
+	},
+	"minimum-stability": "stable",
+	"extra": {
+		"laravel": {
+			"providers": [
+				"Modules\\AiAgent\\Providers\\AiAgentServiceProvider"
+			]
+		}
+	}
+}