refactor(scheduling): consume core participation contract

src/govoplan_scheduling/backend/service.py

@@ -27,6 +27,18 @@ from govoplan_core.core.poll import (
     PollUpdateCommand,
     poll_scheduling_provider,
 )
+from govoplan_core.core.poll_participation import (
+    ANONYMOUS_PASSWORD_REQUIREMENT,
+    PollGovernedInvitationCommand,
+    PollGovernedResponseCommand,
+    PollGovernedResponseRef,
+    PollParticipationContextRef,
+    PollParticipationGatewayProvider,
+    PollParticipationPolicy,
+    PollResponseGatewayRef,
+    participation_token_fingerprint,
+    poll_participation_gateway_provider,
+)
 from govoplan_core.core.policy import (
     SchedulingParticipantPrivacyDecision,
     SchedulingParticipantPrivacyRequest,
@@ -55,18 +67,6 @@ from govoplan_scheduling.backend.security import (
     hash_participant_password,
     verify_participant_password,
 )
-from govoplan_poll.backend.participation import (
-    ANONYMOUS_PASSWORD_REQUIREMENT,
-    PollGovernedInvitationCommand,
-    PollGovernedResponseCommand,
-    PollGovernedResponseRef,
-    PollParticipationContextRef,
-    PollParticipationGatewayProvider,
-    PollParticipationPolicy,
-    PollResponseGatewayRef,
-    participation_token_fingerprint,
-    poll_participation_gateway_provider,
-)
 
 
 class SchedulingError(ValueError):