add day-detail view to monthly history calendar

날짜 셀 클릭 시 그 날 예정된 습관별 완료/실패/미완료 상태를 htmx로 불러와 보여준다.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

app/routers/pages.py

@@ -367,6 +367,20 @@ def _week_context(db: Session, user_id: int, week_start: date) -> dict:
     }
 
 
+@router.get("/history/day/{log_date}")
+def history_day_detail(request: Request, log_date: date, db: Session = Depends(get_db)):
+    current = _current_user_or_redirect(request, db)
+    if isinstance(current, RedirectResponse):
+        return current
+
+    items = log_service.get_day_detail(db, current.id, log_date)
+    return templates.TemplateResponse(
+        request,
+        "partials/day_detail.html",
+        {"log_date": log_date, "items": items},
+    )
+
+
 @router.get("/history")
 def history_page(
     request: Request,