feat(spreadsheet): C 격자 — 확대 이음(zoom() · aislo-grid-zoom 이벤트)

계약 더함 — GridHandle.zoom(): number(1 = 100%). 확대가 바뀔 때마다 격자 root 에서
CustomEvent("aislo-grid-zoom", { detail: { zoom }, bubbles: true }) 를 쏨(sub4 상태줄이 들음).
ORCA 시험 — WheelEvent(ctrlKey · deltaY -300) 로 확대 흉내 → zoom() 1→1.568 · 이벤트
detail.zoom 도 같은 값으로 확인.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VVM3xZ1aUPcUTuW2WZSnwg

A00_Common/spreadsheet/spreadsheet_grid.ts

@@ -399,6 +399,7 @@ export function createGrid(ctx: SpreadsheetContext): GridHandle {
     paneBR.scrollLeft *= zoom / before;
     paneBR.scrollTop *= zoom / before;
     layoutPanes();
+    root.dispatchEvent(new CustomEvent("aislo-grid-zoom", { detail: { zoom }, bubbles: true }));
   }
   root.addEventListener("wheel", onWheel, { passive: false });
 
@@ -935,6 +936,10 @@ export function createGrid(ctx: SpreadsheetContext): GridHandle {
     return { layer: paneLayerOf(r, c), box: screenBoxOf(r, c) };
   }
 
+  function getZoom(): number {
+    return zoom;
+  }
+
   function destroy(): void {
     resize.disconnect();
     paneBR.removeEventListener("scroll", onScroll);
@@ -954,6 +959,7 @@ export function createGrid(ctx: SpreadsheetContext): GridHandle {
     reveal,
     visibleRange,
     editorSlot,
+    zoom: getZoom,
     destroy,
   };
 }

A00_Common/spreadsheet/spreadsheet_view_types.ts

@@ -69,6 +69,8 @@ export interface GridHandle {
   visibleRange(): CellRange;
   /** 편집기를 얹을 층과 칸 자리(화면 좌표 · 병합이면 전체) — D 편집기가 씀 */
   editorSlot(r: number, c: number): { layer: HTMLElement; box: CellBox };
+  /** 지금 확대(1 = 100%) — 바뀌면 `root` 에서 CustomEvent("aislo-grid-zoom", { detail: { zoom } }) 를 쏨(E 상태줄이 들음) */
+  zoom(): number;
   destroy(): void;
 }