Centralize legacy document file saves

docs/modernization/build-inventory.md

@@ -587,8 +587,9 @@ Known local toolchain state:
   close-request executor dispatch/no-op preservation, document-save executor
   dispatch/no-op preservation, save-before-workflow executor dispatch,
   new-document target/resolution/overwrite planning and executor dispatch,
-  document file target, combined save-file overwrite planning, and save-version
-  target decisions without requiring a window, canvas, or message box.
+  document file target, combined save-file overwrite planning and executor
+  dispatch, plus save-version target decisions and executor validation without
+  requiring a window, canvas, or message box.
 - `src/legacy_document_open_services.*` is the current app-shell bridge between
   `pp_app_core` document-open plans and live ABR/PPBR import prompts,
   unsaved-project discard prompts, project opening, layer UI refresh, title
@@ -599,8 +600,11 @@ Known local toolchain state:
   save dialogs, save-version routing, existing-project saves, and
   save-before-workflow prompts. It also bridges accepted new-document plans to
   legacy canvas resize/layer setup, overwrite prompts, title updates, and
-  keyboard/dialog cleanup. Retained legacy UI/canvas execution remains tracked
-  by `DEBT-0040` and `DEBT-0041`.
+  keyboard/dialog 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`,
+  `DEBT-0041`, and `DEBT-0042`.
 - `src/legacy_history_services.*` is the current app-shell bridge between
   `pp_app_core` history plans and legacy `ActionManager`; toolbar and
   `NodeCanvas` hotkeys share it while document-history extraction remains