Plan document file saves in app core

docs/modernization/build-inventory.md

@@ -394,6 +394,9 @@ Known local toolchain state:
 - `pano_cli classify-open` exposes the `pp_app_core` document-open route
   contract as JSON and is covered for project files, ABR imports, PPBR
   imports, and malformed path rejection.
+- `pano_cli plan-document-file` exposes `pp_app_core` document-name
+  validation, legacy `.ppi` path construction, and overwrite-prompt decisions
+  as JSON and is covered for save-now and existing-target overwrite states.
 - `pano_cli simulate-app-session` exposes `pp_app_core` project-open,
   app-close, save, save-as, save-version, and save-before-workflow decisions
   as JSON and is covered for clean, dirty, already-prompting, missing-canvas,
@@ -402,9 +405,9 @@ Known local toolchain state:
   contract for PPI/project files, ABR imports, PPBR imports, inner-dot names,
   and malformed paths before the live `App::open_document` performs UI or
   legacy canvas work.
-- `pp_app_core_document_session_tests` covers clean and dirty app session plus
-  save-request and save-before-workflow decisions without requiring a window,
-  canvas, or message box.
+- `pp_app_core_document_session_tests` covers clean and dirty app session,
+  save-request, save-before-workflow, document file target, and overwrite
+  decisions without requiring a window, canvas, or message box.
 - `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.

docs/modernization/capability-map.md

@@ -13,7 +13,7 @@ and validation command.
 | --- | --- | --- | --- |
 | PPI open/save | `Canvas`, serializer, dialogs | `pp_document`, `pp_assets`, `pano_cli` | Round-trip tiny project, old-version fixture, corrupt/truncated fixture |
 | Open-document routing | `App::open_document` | `pp_app_core`, `pano_cli`, `pp_panopainter_ui`, `pp_document`, `pp_assets` | Project/ABR/PPBR route tests, malformed path tests, CLI route smoke, app open smoke |
-| Document session decisions | `App::open_document`, `App::request_close`, save hotkeys, file menu, dialogs | `pp_app_core`, `pano_cli`, `pp_panopainter_ui` | Clean/dirty/prompt-open/save/save-as/save-version/save-before-workflow decision tests, CLI session smoke, app close/open/save/new/browse smoke |
+| Document session decisions | `App::open_document`, `App::request_close`, save hotkeys, file menu, dialogs | `pp_app_core`, `pano_cli`, `pp_panopainter_ui` | Clean/dirty/prompt-open/save/save-as/save-version/save-before-workflow/name/overwrite decision tests, CLI session and document-file smoke, app close/open/save/new/browse smoke |
 | Version metadata | `scripts/pre-build.py`, `version.*` | build system, `pp_foundation` | Generated header smoke test, missing-tag behavior |
 | Thumbnail generation/read | `Canvas`, `Image` | `pp_assets`, `pp_paint_renderer` | Golden thumbnail, corrupt input |
 | Save-as, overwrite prompts | App/dialogs | `pp_app_core`, `pp_panopainter_ui`, `pp_platform_*` | Decision tests, UI automation, and platform smoke |

docs/modernization/debt.md

@@ -22,7 +22,7 @@ agent or engineer to remove them without reconstructing context from chat.
 | --- | --- | --- | --- | --- | --- | --- |
 | DEBT-0001 | Open | Modernization | Existing platform build files remain alongside new CMake | Required for incremental migration without losing platform coverage | Existing platform builds plus new CMake configure | Remove after all platform builds consume shared CMake targets |
 | DEBT-0002 | Open | Modernization | Vendored SDK and patched libraries retained initially | Some dependencies are SDK-only, patched, or have platform-specific binaries | Dependency inventory and platform build smoke tests | Replace with vcpkg packages or document permanent vendored status after triplet evaluation |
-| DEBT-0003 | Open | Modernization | Existing singletons remain during initial split; `App::open_document`, `App::request_close`, file-menu save actions, `NodeCanvas` save hotkeys, new/open/browse dirty-document workflow prompts, `pano_cli classify-open`, and `pano_cli simulate-app-session` now consume pure `pp_app_core` route/session contracts, but document loading and saving still reach legacy `Canvas::I` and UI singletons | Avoid behavior changes while introducing component boundaries | App launch and component tests; `pp_app_core_document_route_tests`; `pp_app_core_document_session_tests`; `pano_cli classify-open --path D:/Paint/demo.ppi`; `pano_cli simulate-app-session --unsaved --save-intent save-dirty-version`; `pano_cli simulate-app-session --no-canvas`; `ctest --preset desktop-fast --build-config Debug` | Replace singleton reaches with context/service injection at component boundaries |
+| DEBT-0003 | Open | Modernization | Existing singletons remain during initial split; `App::open_document`, `App::request_close`, file-menu save actions, `NodeCanvas` save hotkeys, new/open/browse dirty-document workflow prompts, new/save-as document file naming and overwrite decisions, `pano_cli classify-open`, `pano_cli plan-document-file`, and `pano_cli simulate-app-session` now consume pure `pp_app_core` route/session contracts, but document loading and saving still reach legacy `Canvas::I` and UI singletons | Avoid behavior changes while introducing component boundaries | App launch and component tests; `pp_app_core_document_route_tests`; `pp_app_core_document_session_tests`; `pano_cli classify-open --path D:/Paint/demo.ppi`; `pano_cli plan-document-file --work-dir D:/Paint --name demo --target-exists`; `pano_cli simulate-app-session --unsaved --save-intent save-dirty-version`; `pano_cli simulate-app-session --no-canvas`; `ctest --preset desktop-fast --build-config Debug` | Replace singleton reaches with context/service injection at component boundaries |
 | DEBT-0004 | Open | Modernization | Android, Linux, WebGL, Apple, and AppX build files remain platform-specific until root CMake alignment reaches them | Prevent platform regressions during incremental migration; raw Windows `.sln/.vcxproj` files were removed on 2026-05-31 by user decision | `cmake --preset windows-msvc-default`; platform-specific configure/build smoke checks as each platform is migrated | Root CMake owns every platform source list and package path |
 | DEBT-0005 | Open | Modernization | Temporary local CTest harness is used before Catch2 is wired through vcpkg | `vcpkg` is not currently on PATH, but headless tests need to run now | `ctest --preset desktop-fast --build-config Debug` | Replace `tests/test_harness.h` tests with Catch2 tests once vcpkg toolchain/presets are validated |
 | DEBT-0007 | Open | Modernization | `vcpkg.json` and `windows-msvc-vcpkg-headless` are validated for the headless Windows component matrix, but app targets still use vendored libraries and Android/Apple triplets are not proven | Dependency migration must stay incremental while SDK/patched/vendor dependencies remain in use | `$env:VCPKG_ROOT="C:\Program Files\Microsoft Visual Studio\2022\Community\VC\vcpkg"; cmake --preset windows-msvc-vcpkg-headless`; `ctest --preset desktop-fast-vcpkg --build-config Debug` | Component targets consume vcpkg packages where reliable and desktop app, Android, and Apple triplets are validated or explicitly documented as permanent vendor exceptions |

docs/modernization/roadmap.md

@@ -426,7 +426,9 @@ contract for project files, ABR imports, PPBR imports, and malformed path
 rejection. `pano_cli simulate-app-session` exposes the pure `pp_app_core`
 session decisions used by project-open, app-close, save, save-as, and
 save-version flows, plus the save-before-continue workflow gate used by
-new-document/open/browse dialogs.
+new-document/open/browse dialogs. `pano_cli plan-document-file` exposes the
+same app-core document-name validation, legacy `.ppi` path construction, and
+overwrite prompt decision used by new-document and save-as dialogs.
 `pano_cli parse-layout` exercises the XML layout path. Continue expanding
 document behavior toward legacy Canvas parity and then port OpenGL classes
 behind the renderer boundary.