chore(vocero): remove the legacy ApiPilot integration (#3)

Vocero now retrieves AquaPortal content through authenticated MCP. This removes the obsolete ApiPilot integration from the API and browser while preserving the separately deployed speech pipeline.

Release notes:

- Removed ApiPilot endpoints, configuration, credential overrides, and HTTP/realtime tool execution.
- Removed browser ApiPilot catalog loading and prompt generation while retaining authenticated MCP discovery.
- Updated regression coverage and operating documentation for the retired routes and settings.

Reviewed-on: AquaPortal/s2s#3

vocero-api/scripts/test_docker_image.sh

@@ -38,7 +38,7 @@ with urllib.request.urlopen(base + "/api/config") as response:
     assert json.load(response) == {
         "search": False, "lb": False, "allowDirect": True, "s2sUrl": "",
         "primaryPrompt": "", "reasoningType": "PROXY", "injectProfile": False,
-        "debugPrompt": False, "startSessionMode": "", "theme": "", "apipilot": False,
+        "debugPrompt": False, "startSessionMode": "", "theme": "",
     }
 for path in ["/docs", "/docs/README.md", "/openapi.json"]:
     with urllib.request.urlopen(base + path) as response: