feat(#79): IMP-51 image_overrides axis (u1~u11 backend stamp+CLI+CSS inject + frontend drag/resize+persistence + tests)

Front/client/src/services/userOverridesApi.ts

@@ -7,6 +7,12 @@
 // the four mutation handlers (u7). It does NOT own the schema — any change
 // to KNOWN_AXES must land in u1/u4 first, then reflect here.
 //
+// IMP-51 (#79) u3 — added `image_overrides` (5th axis). `image_id` → percent-
+// of-slide {x,y,w,h}. Mirrors src/user_overrides_io.py KNOWN_AXES (u1) and
+// Front/vite.config.ts KNOWN_USER_OVERRIDES_AXES (u2). Backend stamper +
+// render-time CSS injection ride on u4~u7; the SlideCanvas drag/resize
+// handles that drive this axis ride on u8~u11.
+//
 // Contract (Stage 2 unit u5 summary):
 //   • Typed `getUserOverrides(key)` → returns `Partial<UserOverrides>` from
 //     the GET endpoint. Missing / corrupt / non-object payloads degrade to
@@ -44,12 +50,28 @@ export type ZoneGeometriesOverride = Record<string, ZoneGeometryOverride>;
 /** zone_id → ordered list of section_ids assigned to that zone. */
 export type ZoneSectionsOverride = Record<string, string[]>;
 
+/**
+ * IMP-51 #79 u3 — image_id → percent-of-slide geometry. Matches the user-
+ * content image selector `.slide img[data-image-role="user-content"]`
+ * (stamper in u4) and the render-time CSS injection map (u7). Coordinates
+ * are slide-absolute percent (0–100) so SlideCanvas drag handles (u8~u11)
+ * map 1:1 with the persisted axis without per-zone transforms.
+ */
+export type ImageOverride = {
+  x: number;
+  y: number;
+  w: number;
+  h: number;
+};
+export type ImageOverridesOverride = Record<string, ImageOverride>;
+
 /** Full on-disk schema. All axes optional — file may carry any subset. */
 export interface UserOverrides {
   layout: string;
   frames: FramesOverride;
   zone_geometries: ZoneGeometriesOverride;
   zone_sections: ZoneSectionsOverride;
+  image_overrides: ImageOverridesOverride;
 }
 
 /** Partial-mutation payload. `null` is the explicit clear sentinel (mirrors u4). */