Use pyproject.toml instead of requirements.txt and fix some broken tests.

gateway/integrations/explorer.py

@@ -5,7 +5,7 @@ from typing import Any, Dict, List
 
 from fastapi import HTTPException
 
-from common.guardrails import GuardrailRuleSet, Guardrail, GuardrailAction
+from gateway.common.guardrails import GuardrailRuleSet, Guardrail, GuardrailAction
 from invariant_sdk.async_client import AsyncClient
 from invariant_sdk.types.push_traces import PushTracesRequest, PushTracesResponse
 from invariant_sdk.types.annotations import AnnotationCreate

gateway/integrations/guardrails.py

@@ -8,9 +8,10 @@ from functools import wraps
 
 from fastapi import HTTPException
 import httpx
-from common.guardrails import Guardrail
-from common.request_context import RequestContext
-from common.authorization import (
+
+from gateway.common.guardrails import Guardrail
+from gateway.common.request_context import RequestContext
+from gateway.common.authorization import (
     INVARIANT_GUARDRAIL_SERVICE_AUTHORIZATION_HEADER,
 )