feat(mcp): connect authenticated AquaPortal tools to Vocero (#1)

Vocero needs to query AquaPortal on behalf of the caller selected by the existing phone link. This adds server-owned conversations and MCP tool execution for voice and HTTP reasoning while leaving the speech pipeline unchanged.

Release notes:

- Added browser-bound conversations that keep backend credentials server-side and isolate callers.
- Connected the eight-tool AquaPortal catalog through authenticated Streamable HTTP with full input schemas and structured results.
- Added bounded multi-step tool execution with cancellation, expiry, and stale-result protection.
- Updated browser bootstrap, tool progress, reasoning headers, and conversation cleanup.
- Disabled legacy unscoped content preloads in MCP mode and documented configuration and deployment constraints.
- Preserved disabled-mode contracts and added local SDK, WebSocket, and browser regression coverage.

Reviewed-on: AquaPortal/s2s#1

vocero-api/vocero_api/api/router.py

@@ -2,13 +2,14 @@
 
 from fastapi import APIRouter
 
-from vocero_api.api.routes import apipilot, caller, config, search, sessions
+from vocero_api.api.routes import apipilot, caller, config, conversations, search, sessions
 from vocero_api.models.responses import ReasoningResponse
 from vocero_api.realtime.proxy import realtime_proxy
 from vocero_api.services.reasoning import reasoning
 
 router = APIRouter()
 router.include_router(config.router)
+router.include_router(conversations.router)
 router.include_router(apipilot.router)
 router.add_api_route("/api/reasoning", reasoning, methods=["POST"], response_model=ReasoningResponse)
 router.add_api_websocket_route("/v1/realtime", realtime_proxy)