Extract layer operation planning

docs/modernization/roadmap.md

@@ -250,7 +250,8 @@ Implementation tasks:
 
 - Set C++23 through target features, not raw compiler flags.
 - Add warning profiles:
-  - MSVC: `/W4 /permissive- /Zc:__cplusplus /Zc:preprocessor`.
+  - MSVC: `/W4 /permissive- /Zc:__cplusplus /Zc:preprocessor`, with
+    `C4100` muted temporarily under `DEBT-0019`.
   - Optional MSVC analysis preset: `/analyze`.
   - Clang/GCC: `-Wall -Wextra -Wpedantic -Wconversion -Wshadow
     -Wnull-dereference`.
@@ -289,7 +290,8 @@ Gate:
 
 - Desktop library targets compile with strict diagnostics.
 - New warnings caused by refactor are fixed or locally justified.
-- No global blanket warning suppression for project code.
+- Any global warning suppression must have an open debt entry, validation
+  command, and removal condition.
 
 ## Phase 3: Test Harness And Agent-Ready Automation
 
@@ -484,6 +486,10 @@ legacy `Canvas` resize execution and `ActionManager` history clearing continue.
 `pano_cli plan-layer-rename` exposes the app-core layer rename decision used by
 the live layer rename dialog before legacy `Canvas` layer mutation and
 `ActionManager` undo wiring continue.
+`pano_cli plan-layer-operation` exposes app-core planning for layer add,
+duplicate, select, reorder, remove, opacity, visibility, alpha-lock, blend-mode,
+and highlight actions used by the live layer panel before legacy `Canvas` and
+UI layer execution continue.
 `pp_platform_api` now owns a headless `PlatformServices` interface for
 startup storage path preparation, clipboard text, cursor visibility,
 virtual-keyboard visibility, UI-thread lifecycle hooks, render-context
@@ -1091,11 +1097,19 @@ Results:
   `pano_cli_plan_document_resize_rejects_invalid_selection` passed and expose
   live document-resize planning as JSON automation.
 - `pp_app_core_document_layer_tests` passed, covering changed layer rename,
-  unchanged no-op rename, empty-name rejection, and overlong-name rejection.
+  unchanged no-op rename, empty-name rejection, overlong-name rejection, layer
+  add/duplicate/select/reorder/remove planning, metadata planning, bad-index
+  rejection, bad-opacity rejection, bad-blend-mode rejection, and transient
+  highlight behavior.
 - `pano_cli_plan_layer_rename_smoke`,
   `pano_cli_plan_layer_rename_no_op_smoke`, and
   `pano_cli_plan_layer_rename_rejects_empty_name` passed and expose live
   layer-rename planning as JSON automation.
+- `pano_cli_plan_layer_operation_add_smoke`,
+  `pano_cli_plan_layer_operation_reorder_no_op_smoke`,
+  `pano_cli_plan_layer_operation_highlight_smoke`, and
+  `pano_cli_plan_layer_operation_rejects_bad_opacity` passed and expose live
+  layer-panel operation planning as JSON automation.
 - `pp_app_core_document_sharing_tests` passed, covering saved-path gating before
   platform share execution.
 - `pano_cli_plan_share_file_unsaved_smoke` and