Give tips a date, a scope per child, and a dismissal that sticks

Three faults, all invisible while the tests passed. Advice was built for the
first child only, so a second child got none. The planned days feeding every
count were fetched once per parent and appended to one list, so a couple's
days were counted twice and every intensity and projection derived from them
was wrong. And dismissing a tip forgot the moment the page reloaded.

Tips now carry the date they concern, lifted from figures the rules already
computed, so a view of a month can show only what applies to it. They are
built per child and identified per child, so the same rule firing for two
children is two separate pieces of advice.

A dismissal is stored against a fingerprint of the facts that were dismissed.
When those facts change the advice returns with its new numbers, rather than
one click silencing a warning about a forfeiture that keeps growing.

backend/tests/conftest.py

@@ -24,6 +24,7 @@ from app.repositories_impl.sqlite.leave_wish_repository import SQLiteLeaveWishRe
 from app.repositories_impl.sqlite.parental_leave_repository import SQLiteParentalLeaveRepository
 from app.repositories_impl.sqlite.personal_data_repository import SQLitePersonalDataRepository
 from app.repositories_impl.sqlite.planned_leave_repository import SQLitePlannedLeaveRepository
+from app.repositories_impl.sqlite.tip_dismissal_repository import SQLiteTipDismissalRepository
 from app.repositories_impl.sqlite.user_repository import SQLiteUserRepository
 from app.repositories_impl.sqlite.vacation_days_repository import (
     SQLiteVacationDaysRepository,
@@ -39,6 +40,7 @@ from app.services.child_service import ChildService
 from app.services.day_override_service import DayOverrideService
 from app.services.leave_wish_service import LeaveWishService
 from app.services.planning_service import PlanningService
+from app.services.tips_service import TipsService
 from app.services.vacation_days_service import VacationDaysService
 from app.services.workspace_service import WorkspaceService
 
@@ -308,3 +310,38 @@ async def planning_service(
         vacation_repo,
         planning_engine_service,
     )
+
+
+# ---------------------------------------------------------------------------
+# Tips
+# ---------------------------------------------------------------------------
+
+
+@pytest_asyncio.fixture
+async def tip_dismissal_repo(
+    connection: aiosqlite.Connection,
+) -> SQLiteTipDismissalRepository:
+    return SQLiteTipDismissalRepository(connection)
+
+
+@pytest_asyncio.fixture
+async def tips_service(
+    parental_leave_repo: SQLiteParentalLeaveRepository,
+    planned_leave_repo: SQLitePlannedLeaveRepository,
+    child_repo: SQLiteChildRepository,
+    personal_data_repo: SQLitePersonalDataRepository,
+    vacation_repo: SQLiteVacationDaysRepository,
+    leave_wish_repo: SQLiteLeaveWishRepository,
+    workspace_repo: SQLiteWorkspaceRepository,
+    tip_dismissal_repo: SQLiteTipDismissalRepository,
+) -> TipsService:
+    return TipsService(
+        parental_leave_repo,
+        planned_leave_repo,
+        child_repo,
+        personal_data_repo,
+        vacation_repo,
+        leave_wish_repo,
+        workspace_repo,
+        tip_dismissal_repo,
+    )