Separate user intent from planner output via day assertions

The calendar mixed two kinds of truth in one table. `planned_leave_day` was
simultaneously the allocator's output cache, the user's override store
(`is_pinned`, plus ad-hoc rows with no `wish_id`), and the resource ledger that
analytics and the age-4 maths read. The planner therefore had to ask "am I
allowed to touch this row?" on every sync, and got it wrong at the edges.

Every user assertion is now one `day_assertion` row — a concrete `day_type`
replaces a pinned day, a row with no `wish_id` replaces an ad-hoc day, and
`day_type='none'` replaces `planned_day_exclusion`. `planned_leave_day` becomes
purely derived with a single writer, and `PlanningService.pinned_keys()` is the
single answer to "is this day pinned", used by the allocator's loader, by
`sync_plan` and by the read router alike.

On top of that, every calendar band is now a real event: an ad-hoc band opens
the same full editor as a wish-backed one and saving it promotes it to a
`LeaveWish`, so it can be named, repeated yearly, assigned to either or both
parents, and handed to the planner. "Planering" is a `moveable` toggle plus a
from/to month bound plus a separate lock/unlock action on the days themselves,
replacing a three-rung ladder whose "planner decides" rung set a search window
equal to the drawn dates and so could never move anything.

Bugs found and fixed along the way:

- The plan erased its own history. Fixed windows clip to today, so an elapsed
  auto-placed day fell into `stale_keys` and was deleted on the next sync —
  and a background sync runs on every workspace load. Past rows are now frozen
  and counted as spent.
- Migration 010's downgrade silently destroyed every pinned day and exclusion
  (`is_pinned` returned as DEFAULT 0, the exclusion table came back empty,
  exit 0, no warning). It now reconstructs both from `day_assertion`, and 009
  itemises what it cannot recover before dropping the table.
- Deleting a period left its assertions behind, locking those dates forever
  with no UI path to clear them. Wish deletion now clears them by `wish_id`.
- `DayAssertionService` and `LeaveWishService` committed multi-statement writes
  without a transaction; a crash mid-write diverged the tables or half-deleted
  a series. Both now run in a unit of work.
- A sibling year's shortfall was never surfaced: the toast only inspected the
  edited occurrence's outcome, so a fully unfunded later year rendered as an
  empty band with no warning.
- A flexible window whose bound had entirely elapsed was dropped from the
  proposal with no outcome at all. It now reports as `unplaced`.
- Unlocking a period deleted its days instead of returning them to the planner.
- The e2e global setup posted to a route deleted in this change, which would
  have failed the whole suite before its first test.

Gates: backend 938 tests / 91% coverage, frontend 1351 / 97.4 | 92.2 | 94.37 |
97.4. Migrations 009 and 010 audited against a hand-built realistic database:
the upgrade reconciles exactly and a constraint violation fails safe, leaving
the schema at 008.

Not complete. Step 4's toggle, month picker and lock/unlock action are verified
by browser walk and unit tests, but the partial-lock readout was not exercised.
`ideas.md` §7 adds a full plan for the vacation-forfeiture defect (the planner
detects expiring days and then does nothing about them) — not implemented here.
Remaining smaller items are listed in the session's restructure notes.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01T4wjgbVL4HAC5Rdaw75VbV

backend/app/models/planned_leave.py

@@ -7,33 +7,24 @@ so the wire format can evolve independently.
 from datetime import date, datetime
 from uuid import UUID
 
-from pydantic import BaseModel, Field
+from pydantic import BaseModel
 
 from app.entities.planned_leave import PlannedLeaveDay
 
 
-class PlannedLeaveDayCreate(BaseModel):
-    workspace_id: UUID
-    child_id: UUID
-    parent_personal_data_uuid: UUID
-    date: date
-    day_type: str = Field(pattern="^(sjukpenning|lagsta|vacation)$")
-    is_dubbeldag: bool = False
-    # Which `LeaveWish` produced this day; None = ad-hoc.
-    wish_id: UUID | None = None
-    is_pinned: bool = False
-
-
-class PlannedLeaveDayUpdate(BaseModel):
-    """Partial update — all fields optional."""
-
-    day_type: str | None = Field(None, pattern="^(sjukpenning|lagsta|vacation)$")
-    is_dubbeldag: bool | None = None
-    wish_id: UUID | None = None
-    is_pinned: bool | None = None
-
-
 class PlannedLeaveDayResponse(BaseModel):
+    """Read-only wire shape. `planned_leave_day` is purely derived output
+
+    now (restructure step 3b) — there is no `PlannedLeaveDayCreate`/`Update`
+    model any more; every write goes through `POST /api/plan/sync(-with-
+    wish)` or `POST /api/day-assertions`. `is_pinned` is NOT a column on the
+    entity (migration 010 dropped it) — it is computed live from
+    `DayAssertion` and passed in explicitly by the caller (see
+    `PlanningService._annotate_pinned`), so a lock icon in the calendar UI
+    keeps working unchanged even though nothing on `planned_leave_day`
+    itself carries that state any more.
+    """
+
     id: UUID
     workspace_id: UUID
     child_id: UUID
@@ -47,7 +38,9 @@ class PlannedLeaveDayResponse(BaseModel):
     updated_at: datetime | None
 
     @classmethod
-    def from_entity(cls, entity: PlannedLeaveDay) -> "PlannedLeaveDayResponse":
+    def from_entity(
+        cls, entity: PlannedLeaveDay, is_pinned: bool = False
+    ) -> "PlannedLeaveDayResponse":
         return cls(
             id=entity.id,
             workspace_id=entity.workspace_id,
@@ -57,7 +50,7 @@ class PlannedLeaveDayResponse(BaseModel):
             day_type=entity.day_type,
             is_dubbeldag=entity.is_dubbeldag,
             wish_id=entity.wish_id,
-            is_pinned=entity.is_pinned,
+            is_pinned=is_pinned,
             created_at=entity.created_at,
             updated_at=entity.updated_at,
         )