# V13-FE-038 — KBX UI Performance Decision Required

- **WBS / Requirement / UI / Test:** `V13-FE-038` / `REQ-FE-PERF` / `UI-ALL` / `T-FE-PERF-01`
- **Scope:** 실제 KBX UI 성능 기준과 측정 fixture를 승인 가능한 형태로 고정
- **Source:** `frontend/src/shared/ui/components/KsDataGrid.vue`, `frontend/src/shared/ui/DataGridShell.vue`, `docs/CURRENT/V13-FE-038_GRID_PROVIDER_DECISION.md`, `docs/CURRENT/CATALOGS/WBS_MASTER.csv`, `evidence/V13-FE-005/frontend-build-final_20260813.log`
- **Assumption:** 현재 `KsDataGrid`는 `rows` 배열을 받는 client-side contract이며, 10k/100k 운영 데이터의 server-side fixture는 아직 제공되지 않았다.
- **Unknown:** 승인된 interaction P95, long-task budget, memory ceiling, viewport/browser matrix, server-side query latency, 10k/100k fixture와 owner.
- **Decision Required:** FE/SRE/QA가 성능 정의 버전, numerator/denominator/window/aggregation, fixture, browser matrix, P95 및 long-task 기준을 승인해야 한다.

## Actual observed evidence

- `pnpm --dir frontend build`: PASS; 754 modules transformed.
- Main artifact: 737.32 kB raw / 204.41 kB gzip.
- Vite emits the existing >500 kB warning. This is an observation and debt signal, not a performance-gate PASS.
- `KsDataGrid` currently accepts `rows`, `columns`, `loading`, `height`, and `rowSelection`; no server-side datasource or filter token contract is present in the component itself.
- Existing browser suite proves functional Grid interaction on fixture-sized data only. It does not prove 10k/100k performance.

## Safe next Slice contract

1. Approve a versioned performance definition and fixture checksum.
2. Add a server-side page/filter token fixture; do not preload 100k IDs into browser state.
3. Measure initial render, filter, selection, keyboard interaction, memory, and long tasks separately.
4. Preserve browser/version/OS/artifact SHA and raw traces.
5. Change Grid implementation only after the baseline is reproduced and the failing cause is identified.

## Non-goals

- No arbitrary threshold invention.
- No AG Grid Enterprise dependency.
- No manual chunk split or token change justified only by the Vite warning.
- No claim of 10k/100k performance, P95 compliance, or production SLO.

**Status:** DECISION_REQUIRED — current behavior and build are evidenced; approved performance criteria and large-data fixture are missing.