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/vocero_api/models/requests.py

@@ -29,13 +29,6 @@ class ReasoningRequest(BaseModel):
     episode_id: str | None = None
 
 
-class ApipilotExecuteRequest(BaseModel):
-    """Body for the ApiPilot execute proxy endpoint. Mirrors §2.2 request shape."""
-
-    name: str
-    arguments: dict = {}
-
-
 class QueueEndPayload(BaseModel):
     """A view of a decoded beacon object, preserving the legacy loose value.