add journaling feature: categories, tags, attachments, calendar, and multi-select emotions

Adds an 8th development stage that lets users keep a free-form journal alongside
habit tracking, reusing the existing Google OAuth/DB/PWA infrastructure instead
of a separate project. Users organize entries into custom categories, filter by
a month calendar with day-detail drill-down, attach photos/videos (served via an
authenticated route, never /static), tag entries, and pick multiple emotions per
entry from a curated 9-option set. Includes a global journal prompt bank for
lightweight guided journaling.

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

app/routers/journal.py

@@ -0,0 +1,36 @@
+from fastapi import APIRouter, Depends, HTTPException, Query
+from fastapi.responses import FileResponse
+from sqlalchemy.orm import Session
+
+from app.database import get_db
+from app.models.user import User
+from app.schemas.journal import JournalCategoryReorderRequest
+from app.security import require_login
+from app.services import journal_service
+
+router = APIRouter(prefix="/api/journal", tags=["journal"], dependencies=[Depends(require_login)])
+
+
+@router.get("/media/{attachment_id}")
+def get_media(
+    attachment_id: int,
+    thumbnail: bool = Query(False),
+    db: Session = Depends(get_db),
+    current_user: User = Depends(require_login),
+):
+    attachment = journal_service.get_attachment(db, attachment_id, current_user.id)
+    if attachment is None:
+        raise HTTPException(status_code=404, detail="첨부파일을 찾을 수 없습니다")
+
+    path = attachment.thumbnail_path if (thumbnail and attachment.thumbnail_path) else attachment.file_path
+    return FileResponse(path, filename=attachment.original_filename)
+
+
+@router.post("/categories/reorder")
+def reorder_categories(
+    data: JournalCategoryReorderRequest,
+    db: Session = Depends(get_db),
+    current_user: User = Depends(require_login),
+):
+    journal_service.reorder_categories(db, current_user.id, data.category_ids)
+    return {"ok": True}