Rework balances around per-parent days left and deduce the partner from FK

Manual entry now takes one parent's sjukpenningnivå, lägstanivå and
dubbeldagar left (plus optional reserved days) and derives the rest in
build_snapshot, shared with the scraper. The scraper also reads the
family panel and exposes a partner deduction; with two parents it is
saved as a 'deduced' snapshot (migration 002). Parent count is the single
source of entitlement: one member gets 480 days and 96 savable at age 4,
two get 240 and 48 each. Workspaces are capped at two parents.

Also lands the in-flight squash of migrations 002–011 into the initial
schema and the removal of planning_mode.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

backend/app/services/leave_wish_service.py

@@ -49,6 +49,7 @@ class LeaveWishService:
         parent_mode: str = "either",
         parent_personal_data_uuid: UUID | None = None,
         window_mode: str = "fixed",
+        wants_dubbeldag: bool = False,
     ) -> LeaveWish:
         _validate(
             window_start_month=window_start_month,
@@ -63,6 +64,7 @@ class LeaveWishService:
             parent_mode=parent_mode,
             parent_personal_data_uuid=parent_personal_data_uuid,
             window_mode=window_mode,
+            wants_dubbeldag=wants_dubbeldag,
         )
         now = datetime.now()
         entity = LeaveWish(
@@ -84,6 +86,7 @@ class LeaveWishService:
             parent_mode=parent_mode,
             parent_personal_data_uuid=parent_personal_data_uuid,
             window_mode=window_mode,
+            wants_dubbeldag=wants_dubbeldag,
             created_at=now,
             updated_at=now,
         )
@@ -124,6 +127,7 @@ class LeaveWishService:
         parent_mode: str | None = None,
         parent_personal_data_uuid: UUID | None = None,
         window_mode: str | None = None,
+        wants_dubbeldag: bool | None = None,
         _clear_child_id: bool = False,
         _clear_last_year: bool = False,
         _clear_parent_personal_data_uuid: bool = False,
@@ -192,6 +196,8 @@ class LeaveWishService:
             entity.parent_personal_data_uuid = parent_personal_data_uuid
         if window_mode is not None:
             entity.window_mode = window_mode
+        if wants_dubbeldag is not None:
+            entity.wants_dubbeldag = wants_dubbeldag
 
         _validate(
             window_start_month=entity.window_start_month,
@@ -206,6 +212,7 @@ class LeaveWishService:
             parent_mode=entity.parent_mode,
             parent_personal_data_uuid=entity.parent_personal_data_uuid,
             window_mode=entity.window_mode,
+            wants_dubbeldag=entity.wants_dubbeldag,
         )
         return await self._repo.update(leave_wish_id, entity)
 
@@ -250,6 +257,7 @@ def _validate(
     parent_mode: str,
     parent_personal_data_uuid: UUID | None,
     window_mode: str,
+    wants_dubbeldag: bool = False,
 ) -> None:
     if recurrence not in _VALID_RECURRENCE:
         raise ValidationError(f"recurrence must be one of {_VALID_RECURRENCE}")
@@ -257,6 +265,8 @@ def _validate(
         raise ValidationError(f"parent_mode must be one of {_VALID_PARENT_MODE}")
     if window_mode not in _VALID_WINDOW_MODE:
         raise ValidationError(f"window_mode must be one of {_VALID_WINDOW_MODE}")
+    if wants_dubbeldag and parent_mode != "both":
+        raise ValidationError("wants_dubbeldag may only be set when parent_mode is 'both'")
 
     _validate_month_day(window_start_month, window_start_day, label="window_start")
     _validate_month_day(window_end_month, window_end_day, label="window_end")