fix(clause-kb): backlinks 엔드포인트 parent_id ORM 미매핑 → raw SQL 조회 (500 수정)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

app/api/documents.py

@@ -1904,6 +1904,12 @@ async def get_document_backlinks(
     if not doc or doc.deleted_at is not None:
         raise HTTPException(status_code=404, detail="문서를 찾을 수 없습니다")
 
+    _meta = (await session.execute(sql_text(
+        "SELECT parent_id, clause_code, clause_order FROM documents WHERE id = :id"
+    ).bindparams(id=doc_id))).mappings().first()
+    _parent_id = _meta["parent_id"] if _meta else None
+    _clause_code = _meta["clause_code"] if _meta else None
+    _clause_order = _meta["clause_order"] if _meta else None
     forward = (
         await session.execute(
             sql_text(
@@ -1934,7 +1940,7 @@ async def get_document_backlinks(
     ).mappings().all()
 
     prev = nxt = None
-    if doc.parent_id is not None and doc.clause_order is not None:
+    if _parent_id is not None and _clause_order is not None:
         prow = (
             await session.execute(
                 sql_text(
@@ -1944,7 +1950,7 @@ async def get_document_backlinks(
                       AND clause_order < :ord
                     ORDER BY clause_order DESC LIMIT 1
                     """
-                ).bindparams(pid=doc.parent_id, ord=doc.clause_order)
+                ).bindparams(pid=_parent_id, ord=_clause_order)
             )
         ).mappings().first()
         nrow = (
@@ -1956,7 +1962,7 @@ async def get_document_backlinks(
                       AND clause_order > :ord
                     ORDER BY clause_order ASC LIMIT 1
                     """
-                ).bindparams(pid=doc.parent_id, ord=doc.clause_order)
+                ).bindparams(pid=_parent_id, ord=_clause_order)
             )
         ).mappings().first()
         prev = ClauseTocItem(**dict(prow)) if prow else None
@@ -1964,8 +1970,8 @@ async def get_document_backlinks(
 
     return BacklinksResponse(
         doc_id=doc_id,
-        clause_code=doc.clause_code,
-        parent_id=doc.parent_id,
+        clause_code=_clause_code,
+        parent_id=_parent_id,
         prev=prev,
         next=nxt,
         forward=[BacklinkRef(**dict(r)) for r in forward],