feat: refine subject visits and project workflows

Add early termination visit workflow with ordering, non-applicable visit handling, visit window display, and medication adherence support.

Extend monitoring visit issue template fields, site scoping, setup draft project info handling, login security UI, attachment behavior, and related tests/migrations.

backend/app/api/v1/visits.py

@@ -9,7 +9,8 @@ from app.crud import site as site_crud
 from app.crud import subject as subject_crud
 from app.crud import study as study_crud
 from app.crud import visit as visit_crud
-from app.schemas.visit import VisitCreate, VisitRead, VisitUpdate
+from app.schemas.subject import SubjectUpdate
+from app.schemas.visit import EarlyTerminationCreate, VisitCreate, VisitRead, VisitUpdate
 
 router = APIRouter()
 
@@ -110,6 +111,60 @@ async def create_visit(
     return visit
 
 
+@router.post(
+    "/early-termination",
+    response_model=VisitRead,
+    status_code=status.HTTP_201_CREATED,
+    dependencies=[Depends(require_study_roles(["PM", "CRA"])), Depends(require_study_not_locked())],
+)
+async def create_early_termination(
+    study_id: uuid.UUID,
+    subject_id: uuid.UUID,
+    termination_in: EarlyTerminationCreate,
+    db: AsyncSession = Depends(get_db_session),
+    current_user=Depends(get_current_user),
+) -> VisitRead:
+    subject = await _ensure_subject(db, study_id, subject_id)
+    await _ensure_subject_active(db, subject)
+    reason = termination_in.reason.strip()
+    if not reason:
+        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail="提前终止原因不能为空")
+    if subject.baseline_date and termination_in.termination_date < subject.baseline_date:
+        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail="提前终止日期不能早于基线/治疗日期")
+
+    try:
+        visit = await visit_crud.create_early_termination_visit(
+            db,
+            study_id=study_id,
+            subject=subject,
+            termination_date=termination_in.termination_date,
+            reason=reason,
+            notes=termination_in.notes,
+        )
+    except ValueError as exc:
+        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail=str(exc)) from exc
+    await subject_crud.update_subject(
+        db,
+        subject,
+        SubjectUpdate(
+            status="DROPPED",
+            completion_date=termination_in.termination_date,
+            drop_reason=reason,
+        ),
+    )
+    await audit_crud.log_action(
+        db,
+        study_id=study_id,
+        entity_type="visit",
+        entity_id=visit.id,
+        action="CREATE_EARLY_TERMINATION",
+        detail=f"参与者 {subject.subject_no} 已提前终止",
+        operator_id=current_user.id,
+        operator_role=current_user.role,
+    )
+    return visit
+
+
 @router.patch(
     "/{visit_id}",
     response_model=VisitRead,