feat(#73): IMP-44 u1~u5 layout override unknown-key guard + frontend zone_geometries validation

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Front/client/src/pages/Home.tsx

@@ -19,6 +19,7 @@ import {
   deriveUserOverridesKey,
   applyPersistedNonFrameOverrides,
   remapPersistedFramesToZoneFrames,
+  validateZoneGeometriesAgainstLayout,
 } from "../utils/slidePlanUtils";
 import {
   parseMdxFile,
@@ -154,6 +155,21 @@ export default function Home() {
         }
         carriedZoneSections[targetPos].push(...zone.section_ids);
       });
+      // IMP-44 (#73) u4 — clear in-memory zone_geometries on layout flip.
+      // The persisted keys were valid for the *prior* preset; carrying them
+      // forward into the new preset would either trip the u1/u2 backend
+      // [override-warning] guards (foreign keys dropped, override_applied
+      // forced back to None) or partially apply on shared keys. Drop them
+      // up-front so the new layout starts from a clean even-split baseline,
+      // and persist a clear sentinel (null) so a subsequent reopen does not
+      // resurrect the stale snapshot from user_overrides.json.
+      const priorGeoms = p.userSelection.overrides.zone_geometries;
+      const hadPriorGeoms =
+        priorGeoms && typeof priorGeoms === "object" && Object.keys(priorGeoms).length > 0;
+      if (p.uploadedFile && hadPriorGeoms) {
+        const key = deriveUserOverridesKey(p.uploadedFile.name);
+        void saveUserOverrides(key, { zone_geometries: null });
+      }
       return {
         ...p,
         userSelection: {
@@ -162,6 +178,7 @@ export default function Home() {
             ...p.userSelection.overrides,
             layout_preset: layoutId,
             zone_sections: carriedZoneSections,
+            zone_geometries: {},
           },
           selectedZoneId: null,
           selectedRegionId: null,
@@ -329,9 +346,28 @@ export default function Home() {
 
       // zone-geometry override — backend 의 build_layout_css 에 전달 (horizontal-2 /
       // vertical-2 만 적용). zone_id (top/bottom/...) → slide-body 내부 0~1 비율.
+      // IMP-44 (#73) u4 — validate against the active layout *before* the
+      // round-trip so foreign-preset keys never reach the backend. Mirrors
+      // the u1/u2 WARN+DROP guards on the frontend side: dropped keys surface
+      // as a toast (so the user knows why their resize "vanished"), and only
+      // the `kept` subset is forwarded. The active layout = the layout the
+      // backend will use, which is `overrides.layout` when the user has set
+      // one, else the default slidePlan preset (mirrors backend resolution).
       const zoneGeometries = state.userSelection.overrides.zone_geometries;
       if (zoneGeometries && Object.keys(zoneGeometries).length > 0) {
-        overrides.zoneGeometries = zoneGeometries;
+        const activeLayout = overrides.layout ?? sourcePlan.layout_preset;
+        const validation = validateZoneGeometriesAgainstLayout(
+          zoneGeometries,
+          activeLayout,
+        );
+        if (Object.keys(validation.dropped).length > 0) {
+          toast.error(
+            `zone_geometries layout-mismatch: dropped ${Object.keys(validation.dropped).join(", ")} (expected ${validation.expectedPositions.join(", ") || "—"}; layout=${activeLayout}).`,
+          );
+        }
+        if (Object.keys(validation.kept).length > 0) {
+          overrides.zoneGeometries = validation.kept;
+        }
       }
 
       // 2026-05-22 — IMP-08 B-3 원래 동작 (sameAsDefault with effectiveSlidePlan) 복귀.

Front/client/src/utils/slidePlanUtils.ts

@@ -1,5 +1,6 @@
 import type { UserSelection, SlidePlan, Zone, InternalRegion, LayoutPresetId } from "../types/designAgent";
 import type { UserOverrides } from "../services/userOverridesApi";
+import { computeZonePositions } from "../services/designAgentApi";
 
 // ─── IMP-52 u6 — restore-on-reopen helpers (pure, exported for testing) ────
 // These helpers compose persisted `user_overrides.json` payloads (typed by
@@ -320,3 +321,77 @@ export function getEffectiveLayoutId(slidePlan: SlidePlan | null, selection: Use
   if (selection.overrides.layout_preset) return selection.overrides.layout_preset;
   return slidePlan?.layout_preset || 'single';
 }
+
+// ─── IMP-44 (#73) u3 — zone_geometries layout-mismatch validation ───────────
+// Pure helper paired with the backend [override-warning] guards added in u1
+// (1-D horizontal-2 / vertical-2 branches of `build_layout_css`) and u2 (2-D
+// `_override_to_grid_tracks` call site). Same WARN+DROP / KEEP-known contract,
+// but expressed on the frontend so handleGenerate (u4) can validate against
+// the active layout *before* forwarding and surface a toast on dropped keys.
+//
+// Source of truth for expected positions = `computeZonePositions(layoutPreset)`
+// (designAgentApi.ts), which mirrors backend `layouts.yaml` (positions field).
+// Unknown layout (null / undefined / not in LAYOUT_PRESET_IDS) ⇒ fail-safe
+// drop-all: caller has no contract for projecting geometries onto an unknown
+// preset, so we keep zero keys rather than passing them through verbatim.
+
+export interface ZoneGeometryValue {
+  x: number;
+  y: number;
+  w: number;
+  h: number;
+}
+
+export interface ZoneGeometriesValidationResult {
+  kept: Record<string, ZoneGeometryValue>;
+  dropped: Record<string, ZoneGeometryValue>;
+  expectedPositions: string[];
+  valid: boolean;
+}
+
+export function validateZoneGeometriesAgainstLayout(
+  geoms: Record<string, ZoneGeometryValue> | null | undefined,
+  layoutPreset: LayoutPresetId | string | null | undefined,
+): ZoneGeometriesValidationResult {
+  const kept: Record<string, ZoneGeometryValue> = {};
+  const dropped: Record<string, ZoneGeometryValue> = {};
+  const safeGeoms =
+    geoms && typeof geoms === "object" && !Array.isArray(geoms) ? geoms : null;
+
+  // Unknown-layout fail-safe — drop everything; no expected positions known.
+  if (typeof layoutPreset !== "string" || !LAYOUT_PRESET_IDS.has(layoutPreset)) {
+    if (safeGeoms) {
+      for (const [k, v] of Object.entries(safeGeoms)) {
+        dropped[k] = v;
+      }
+    }
+    return {
+      kept,
+      dropped,
+      expectedPositions: [],
+      valid: Object.keys(dropped).length === 0,
+    };
+  }
+
+  const expectedPositions = computeZonePositions(
+    layoutPreset as LayoutPresetId,
+  ).map((p) => p.name);
+  const expectedSet = new Set(expectedPositions);
+
+  if (safeGeoms) {
+    for (const [k, v] of Object.entries(safeGeoms)) {
+      if (expectedSet.has(k)) {
+        kept[k] = v;
+      } else {
+        dropped[k] = v;
+      }
+    }
+  }
+
+  return {
+    kept,
+    dropped,
+    expectedPositions,
+    valid: Object.keys(dropped).length === 0,
+  };
+}