Validate PPI project layout

docs/modernization/roadmap.md

@@ -312,9 +312,9 @@ input. A synchronous event dispatcher, structured logging facade, bounded FIFO
 task queue, and deterministic `TraceRecorder` now record
 component/name/thread/frame/stroke metadata with filtering, capacity, and
 invalid-end tests. `pp_assets` has started with PNG/JPEG signature detection,
-PNG IHDR metadata parsing, PPI header recognition, and a pure typed settings
-document model, with corrupt/truncated/unsupported, extreme-dimension, and
-key/value limit tests.
+PNG IHDR metadata parsing, PPI header/project byte-layout recognition, and a
+pure typed settings document model, with corrupt/truncated/unsupported,
+extreme-dimension, and key/value limit tests.
 `pp_paint` has started with pure brush parameter validation/stamp evaluation,
 CPU reference math for the five current shader blend modes, and deterministic
 stroke spacing/interpolation plus a pure text stroke-script parser.
@@ -327,7 +327,9 @@ started with deterministic CPU layer compositing over renderer extents using
 the paint blend reference. `pp_ui_core` has started with XML-layout-facing
 length parsing, color parsing, tinyxml-backed layout XML parsing, and invalid
 input tests.
-`pano_cli inspect-image` exposes PNG IHDR metadata as JSON, and
+`pano_cli inspect-image` exposes PNG IHDR metadata as JSON,
+`pano_cli inspect-project` reports validated PPI thumbnail/body byte layout,
+and
 `pano_cli create-document` can create simple animation documents with explicit
 frame count/duration, and `pano_cli simulate-stroke` exercises the pure stroke
 sampler for scripted-stroke automation. `pano_cli simulate-stroke-script`
@@ -566,7 +568,8 @@ Results:
 - `pp_foundation_trace_tests` passed.
 - `pp_assets_image_format_tests` passed.
 - `pp_assets_image_metadata_tests` passed.
-- `pp_assets_ppi_header_tests` passed.
+- `pp_assets_ppi_header_tests` passed, including PPI thumbnail/body layout
+  validation.
 - `pp_assets_settings_document_tests` passed.
 - `pp_paint_brush_tests` passed.
 - `pp_paint_blend_tests` passed.
@@ -586,6 +589,8 @@ Results:
   test.
 - `pano_cli_inspect_png_metadata_smoke` passed and reports PNG metadata JSON
   for the tiny IHDR fixture.
+- `pano_cli_inspect_project_layout_smoke` passed and reports PPI
+  thumbnail/body byte layout JSON.
 - `pano_cli_parse_layout_smoke` passed.
 - `pano_cli_simulate_stroke_smoke` passed and reports deterministic stroke
   sample counts/distances.