feat(core): configure bounded scheduling cancellation notices

src/govoplan_core/core/install_config.py

@@ -340,6 +340,7 @@ CELERY_ENABLED=true
 REDIS_URL=redis://127.0.0.1:6379/0
 CELERY_QUEUES=send_email,append_sent,notifications,calendar,default
 CALENDAR_OUTBOX_TERMINAL_RETENTION_DAYS=90
+SCHEDULING_CANCELLATION_NOTICE_DAYS=30
 
 # Deployment-wide connector egress policy. Enable private networks only when
 # this installation intentionally integrates with internal services.
@@ -405,6 +406,7 @@ REDIS_URL=redis://127.0.0.1:56379/0
 CELERY_ENABLED=true
 CELERY_QUEUES=send_email,append_sent,notifications,calendar,default
 CALENDAR_OUTBOX_TERMINAL_RETENTION_DAYS=90
+SCHEDULING_CANCELLATION_NOTICE_DAYS=30
 
 GOVOPLAN_CONNECTOR_ALLOW_PRIVATE_NETWORKS=true
 GOVOPLAN_CONNECTOR_MAX_STRUCTURED_RESPONSE_BYTES=16777216

src/govoplan_core/settings.py

@@ -76,6 +76,12 @@ class Settings(BaseSettings):
         ge=0,
         alias="CALENDAR_OUTBOX_TERMINAL_RETENTION_DAYS",
     )
+    scheduling_cancellation_notice_days: int = Field(
+        default=30,
+        ge=1,
+        le=90,
+        alias="SCHEDULING_CANCELLATION_NOTICE_DAYS",
+    )
     mock_mailbox_dir: str = Field(default="runtime/mock-mailbox", alias="MOCK_MAILBOX_DIR")
 
     # Development bootstrap only. Do not use this in production.