fix(poll): harden lifecycle policy boundaries

src/govoplan_poll/backend/transitions.py

@@ -22,6 +22,7 @@ class PollTransitionRule:
     source_statuses: frozenset[str]
     target_status: str | None
     restore_archived_status: bool = False
+    missing_restore_target_status: str | None = None
 
 
 @dataclass(frozen=True)
@@ -56,8 +57,12 @@ class PollTransitionPolicy:
             if rule.restore_archived_status:
                 if rule.target_status is not None:
                     raise ValueError(f"Restoring transition {action!r} cannot have a fixed target")
+                if rule.missing_restore_target_status not in (POLL_STATUSES - {"archived"}) | {None}:
+                    raise ValueError(f"Restoring transition {action!r} has an invalid missing-origin target")
             elif rule.target_status not in POLL_STATUSES:
                 raise ValueError(f"Poll transition rule {action!r} has an unknown target status")
+            elif rule.missing_restore_target_status is not None:
+                raise ValueError(f"Non-restoring transition {action!r} cannot have a missing-origin target")
         self._rules = MappingProxyType(normalized)
 
     @property
@@ -97,6 +102,7 @@ DEFAULT_POLL_TRANSITION_POLICY = PollTransitionPolicy(
             source_statuses=frozenset({"archived"}),
             target_status=None,
             restore_archived_status=True,
+            missing_restore_target_status="draft",
         ),
     }
 )
@@ -125,9 +131,12 @@ class PollTransitionEngine:
 
         target_status = rule.target_status
         if rule.restore_archived_status:
-            if archived_from_status not in POLL_STATUSES - {"archived"}:
+            if archived_from_status is None and rule.missing_restore_target_status is not None:
+                target_status = rule.missing_restore_target_status
+            elif archived_from_status not in POLL_STATUSES - {"archived"}:
                 raise ValueError("Archived poll has no valid status to restore")
-            target_status = archived_from_status
+            else:
+                target_status = archived_from_status
         assert target_status is not None
         return PollTransitionPlan(action=action, from_status=current_status, to_status=target_status)
 
@@ -140,7 +149,11 @@ class PollTransitionEngine:
         actions: list[PollTransitionAvailability] = []
         for action in POLL_TRANSITION_ACTIONS:
             rule = self.policy.rules[action]
-            target_status = archived_from_status if rule.restore_archived_status else rule.target_status
+            target_status = (
+                archived_from_status or rule.missing_restore_target_status
+                if rule.restore_archived_status
+                else rule.target_status
+            )
             try:
                 self.plan(
                     current_status=current_status,