wip(handoff): restore backend suite to green

Co-Authored-By: Codex <noreply@openai.com>

backend/app/api/endpoints/shares.py

@@ -20,6 +20,7 @@ from app.core.audit import log_audit
 from app.core.rate_limit import limiter
 
 router = APIRouter(tags=["shares"])
+public_router = APIRouter(tags=["shares"])
 
 
 def build_share_response(share: SessionShare) -> ShareResponse:
@@ -206,7 +207,7 @@ async def _get_optional_user(request: Request, db: AsyncSession) -> Optional[Use
         return None
 
 
-@router.get("/share/{share_token}", response_model=SharePublicView)
+@public_router.get("/share/{share_token}", response_model=SharePublicView)
 @limiter.limit("30/minute")
 async def access_share(
     share_token: str,