Add targeted PPI payload automation

docs/modernization/build-inventory.md

@@ -122,9 +122,11 @@ Known local toolchain state:
   `pano_cli_load_project_metadata_smoke`.
 - `pano_cli save-project` writes generated multi-layer, multi-frame PPI files
   with configurable layer opacity, blend mode, alpha lock, and visibility
-  through `pp_assets` and is covered by `pano_cli_save_project_roundtrip_smoke`
+  through `pp_assets`; test dirty-face payloads can target explicit generated
+  layer/frame slots. It is covered by `pano_cli_save_project_roundtrip_smoke`
   and `pano_cli_save_project_payload_roundtrip_smoke`, which reload generated
-  metadata-only and dirty-face-payload projects through `pano_cli load-project`.
+  metadata-only and targeted dirty-face-payload projects through
+  `pano_cli load-project`.
 - `pano_cli create-document` supports `--frames` and `--frame-duration-ms` and
   is covered by `pano_cli_create_animation_document_smoke`.
 - `pano_cli simulate-document-edits` exercises pure document layer/frame edit
@@ -287,9 +289,10 @@ Known local toolchain state:
   automation and is covered by `pano_cli_export_image_roundtrip_smoke`; full
   legacy canvas export remains a future CLI task.
 - `pano_cli save-project` exposes generated multi-layer, multi-frame PPI
-  writing with layer metadata through JSON automation and is covered by
-  metadata-only and dirty-face-payload round-trip smoke tests; full legacy
-  canvas save parity remains tracked by DEBT-0013.
+  writing with layer metadata and targeted dirty-face layer/frame payloads
+  through JSON automation and is covered by metadata-only and
+  dirty-face-payload round-trip smoke tests; full legacy canvas save parity
+  remains tracked by DEBT-0013.
 - `pp_ui_core` consumes vcpkg tinyxml2 only when `PP_USE_VCPKG_TINYXML2=ON`
   through the vcpkg preset; default and Android validation still use the
   retained vendored fallback tracked by DEBT-0012.