feat(core): define atomic poll option ordering

src/govoplan_core/core/poll.py

@@ -73,6 +73,18 @@ class PollOptionUpdateCommand:
     metadata: Mapping[str, object] = field(default_factory=dict)
 
 
+@dataclass(frozen=True, slots=True)
+class PollOptionOrderCommand:
+    """Complete active option order supplied by an owning module.
+
+    Providers must reject partial, duplicate, or unknown option collections.
+    An exact repeat is an idempotent no-op. Reordering changes positions only;
+    option identities and their existing answers remain valid.
+    """
+
+    option_ids: tuple[str, ...]
+
+
 @dataclass(frozen=True, slots=True)
 class PollInvitationCommand:
     respondent_id: str | None = None
@@ -183,6 +195,18 @@ class PollSchedulingProvider(Protocol):
 
         ...
 
+    def reorder_options(
+        self,
+        session: object,
+        *,
+        tenant_id: str,
+        poll_id: str,
+        command: PollOptionOrderCommand,
+    ) -> PollRef:
+        """Atomically replace the complete active option order."""
+
+        ...
+
     def open_poll(self, session: object, *, tenant_id: str, poll_id: str) -> PollRef:
         ...