docs(parity): mirror 40250 layout for the logic layer; evaluate embedded Python UI

- SKILL.md: logic units port into extension/src/port/<Lib>/<File>, platform
  adapters under extension/src/platform; legacy GDScript owners are migration
  sources; python layer frozen until the embedding decision
- port_map.py: logic/python/platform layers with per-layer progress, queue
  --layer, LEGACY layout check; inventory adds EterBase, EterPythonLib,
  ScriptLib, SpeedTreeLib, SphereLib, EterImageLib
- py_embed_spike.py + docs/PYTHON-EMBED-EVAL.md: the 40250 system.py bootstrap
  loads 67/74 root modules unchanged under CPython 2.7 with stub natives

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

.agents/skills/metin2-40250-parity-audit/scripts/audit_source_coverage.py

@@ -122,7 +122,7 @@ def manifest_data(repo: pathlib.Path) -> tuple[set[str], dict[str, list[str]]]:
     return listed, owners
 
 
-def active_project_sources(reference_root: pathlib.Path) -> set[str]:
+def active_project_sources(reference_root: pathlib.Path, dirs: tuple[str, ...] = REFERENCE_DIRS) -> set[str]:
     active: set[str] = set()
     for project in sorted((reference_root.parent / "vs_files").glob("*/*.vcxproj")):
         try:
@@ -140,7 +140,7 @@ def active_project_sources(reference_root: pathlib.Path) -> set[str]:
                 relative = candidate.relative_to(reference_root.resolve())
             except ValueError:
                 continue
-            if relative.parts and relative.parts[0] in REFERENCE_DIRS:
+            if relative.parts and relative.parts[0] in dirs:
                 if relative.suffix.lower() in SOURCE_SUFFIXES:
                     active.add(relative.as_posix())
     return active