Add soft-delete + recovery and tree-wide graph endpoints

Tree and person soft-delete + restore (owner-only for trees, editor for people) with recovery listings (?deleted=true); the worker already purges past the 30-day window. Adds tree-wide GET /relationships and /events so the family/pedigree view loads the whole graph in a few calls. 27 tests pass.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Signed-off-by: Justin Paul <justin@jpaul.me>

backend/app/api/v1/events.py

@@ -20,6 +20,15 @@ async def create_event(
     return EventRead.model_validate(event)
 
 
+@router.get("/{tree_id}/events", response_model=list[EventRead])
+async def list_tree_events(
+    tree_id: uuid.UUID, session: SessionDep, current: CurrentUser
+) -> list[EventRead]:
+    tree = await tree_service.get_tree(session, viewer_id=current.id, tree_id=tree_id)
+    events = await event_service.list_events(session, viewer_id=current.id, tree=tree)
+    return [EventRead.model_validate(e) for e in events]
+
+
 @router.get("/{tree_id}/persons/{person_id}/events", response_model=list[EventRead])
 async def list_person_events(
     tree_id: uuid.UUID, person_id: uuid.UUID, session: SessionDep, current: CurrentUser