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/tests/unit/test_authz.py

@@ -194,6 +194,23 @@ class TestNoTokenIsUnauthenticated:
         resp = await anon_client.get(f"/api/vacation-days/workspace/{uuid4()}")
         assert resp.status_code == 401
 
+    async def test_day_assertions_create_requires_auth(self, anon_client: AsyncClient) -> None:
+        resp = await anon_client.post(
+            "/api/day-assertions",
+            json={
+                "workspace_id": str(uuid4()),
+                "child_id": str(uuid4()),
+                "parent_personal_data_uuid": str(uuid4()),
+                "date": "2030-01-01",
+                "day_type": "vacation",
+            },
+        )
+        assert resp.status_code == 401
+
+    async def test_day_assertions_list_requires_auth(self, anon_client: AsyncClient) -> None:
+        resp = await anon_client.get(f"/api/day-assertions/workspace/{uuid4()}")
+        assert resp.status_code == 401
+
 
 # ---------------------------------------------------------------------------
 # F3 — a real id from a DIFFERENT workspace must 404, never 403.
@@ -504,21 +521,6 @@ class TestForeignWorkspaceIdIs404:
         resp = await client.get(f"/api/vacation-days/workspace/{two_workspaces.ws_b.id}")
         assert resp.status_code == 404
 
-    async def test_planned_days_create_foreign_child(
-        self, client: AsyncClient, two_workspaces: _TwoWorkspaces
-    ) -> None:
-        resp = await client.post(
-            "/api/planned-days",
-            json={
-                "workspace_id": str(two_workspaces.ws_a.id),
-                "child_id": str(two_workspaces.child_b.id),
-                "parent_personal_data_uuid": str(_CALLER_PD_UUID),
-                "date": "2030-06-01",
-                "day_type": "vacation",
-            },
-        )
-        assert resp.status_code == 404
-
     async def test_planned_days_list_by_child_foreign(
         self, client: AsyncClient, two_workspaces: _TwoWorkspaces
     ) -> None:
@@ -550,38 +552,55 @@ class TestForeignWorkspaceIdIs404:
         resp = await client.get(f"/api/planned-days/workspace/{two_workspaces.ws_b.id}")
         assert resp.status_code == 404
 
-    async def test_planned_days_update_foreign(
-        self, client: AsyncClient, connection: aiosqlite.Connection, two_workspaces: _TwoWorkspaces
+    async def test_day_assertions_create_foreign_child(
+        self, client: AsyncClient, two_workspaces: _TwoWorkspaces
     ) -> None:
-        repo = SQLitePlannedLeaveRepository(connection)
-        row = await repo.create(
-            PlannedLeaveDay(
-                id=uuid4(),
-                workspace_id=two_workspaces.ws_b.id,
-                child_id=two_workspaces.child_b.id,
-                parent_personal_data_uuid=two_workspaces.pd_b.uuid,
-                date=date(2030, 6, 2),
-                day_type="vacation",
-            )
+        resp = await client.post(
+            "/api/day-assertions",
+            json={
+                "workspace_id": str(two_workspaces.ws_a.id),
+                "child_id": str(two_workspaces.child_b.id),
+                "parent_personal_data_uuid": str(_CALLER_PD_UUID),
+                "date": "2030-06-01",
+                "day_type": "vacation",
+            },
         )
-        resp = await client.put(f"/api/planned-days/{row.id}", json={"day_type": "sjukpenning"})
         assert resp.status_code == 404
 
-    async def test_planned_days_delete_foreign(
-        self, client: AsyncClient, connection: aiosqlite.Connection, two_workspaces: _TwoWorkspaces
+    async def test_day_assertions_create_foreign_workspace(
+        self, client: AsyncClient, two_workspaces: _TwoWorkspaces
     ) -> None:
-        repo = SQLitePlannedLeaveRepository(connection)
-        row = await repo.create(
-            PlannedLeaveDay(
-                id=uuid4(),
-                workspace_id=two_workspaces.ws_b.id,
-                child_id=two_workspaces.child_b.id,
-                parent_personal_data_uuid=two_workspaces.pd_b.uuid,
-                date=date(2030, 6, 3),
-                day_type="vacation",
-            )
+        resp = await client.post(
+            "/api/day-assertions",
+            json={
+                "workspace_id": str(two_workspaces.ws_b.id),
+                "child_id": str(two_workspaces.child_b.id),
+                "parent_personal_data_uuid": str(two_workspaces.pd_b.uuid),
+                "date": "2030-06-01",
+                "day_type": "vacation",
+            },
+        )
+        assert resp.status_code == 404
+
+    async def test_day_assertions_list_foreign_workspace(
+        self, client: AsyncClient, two_workspaces: _TwoWorkspaces
+    ) -> None:
+        resp = await client.get(f"/api/day-assertions/workspace/{two_workspaces.ws_b.id}")
+        assert resp.status_code == 404
+
+    async def test_day_assertions_clear_foreign_workspace(
+        self, client: AsyncClient, two_workspaces: _TwoWorkspaces
+    ) -> None:
+        resp = await client.request(
+            "DELETE",
+            "/api/day-assertions",
+            params={
+                "workspace_id": str(two_workspaces.ws_b.id),
+                "child_id": str(two_workspaces.child_b.id),
+                "parent_personal_data_uuid": str(two_workspaces.pd_b.uuid),
+                "date": "2030-06-01",
+            },
         )
-        resp = await client.delete(f"/api/planned-days/{row.id}")
         assert resp.status_code == 404
 
     async def test_fetch_data_manual_foreign_workspace(