Prepare document snapshots before legacy saves

docs/modernization/build-inventory.md

@@ -265,7 +265,8 @@ powershell -ExecutionPolicy Bypass -File scripts\automation\apple-remote-build.p
   state toward `pp_document::CanvasDocument`, including dimensions, active
   layer/frame, layer visibility/opacity/alpha/blend metadata, frame durations,
   captured RGBA8 face payloads, and remaining renderer payload-readback counts,
-  and is covered by `pano_cli_plan_canvas_document_snapshot_smoke` plus the
+  plus the save-readiness report now consumed before retained live saves, and
+  is covered by `pano_cli_plan_canvas_document_snapshot_smoke` plus the
   payload-bearing snapshot smoke.
 - `pano_cli save-document-project` writes that pure document export to a PPI
   file and is covered by `pano_cli_save_document_project_roundtrip_smoke`,
@@ -1090,7 +1091,10 @@ powershell -ExecutionPolicy Bypass -File scripts\automation\apple-remote-build.p
   cleanup. Accepted Save As and Save Version plans now also
   route through this bridge before reaching legacy project-save execution,
   overwrite prompts, document field updates, title updates, and keyboard/dialog
-  cleanup. Retained legacy UI/canvas execution remains tracked by `DEBT-0040`,
+  cleanup. Existing Save, Save As, Save Version, and save-before-workflow
+  prepare and log a payload-bearing canvas document snapshot report before
+  delegating to retained `Canvas::project_save`. Retained legacy UI/canvas
+  execution and actual save serialization remain tracked by `DEBT-0040`,
   `DEBT-0041`, and `DEBT-0042`.
 - `src/legacy_document_export_services.*` is the current app-shell bridge
   between `pp_app_core` document export execution plans and live equirectangular,