chore: checkpoint web Blender migration source, tools and docs

Accumulated uncommitted work: GHOST Web backend, WebGL/GPU web layer,
web workflow engine and protocol, tooling, docs and task records.
Large generated evidence, user-testing archives, build snapshots and
imported test assets remain untracked.

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

blender-5.2.0/scripts/modules/addon_utils.py

@@ -371,6 +371,16 @@ def enable(module_name, *, default_set=False, persistent=False, refresh_handled=
             import traceback
             traceback.print_exc()
 
+    # Keep desktop diagnostics, but also report consumed import/register errors
+    # to the embedded startup transaction before it can publish native UI.
+    if sys.platform == "emscripten":
+        import _webengine
+        handle_error_original = handle_error
+
+        def handle_error(ex):
+            _webengine.startup_registration_failed()
+            handle_error_original(ex)
+
     if (is_extension := module_name.startswith(_ext_base_pkg_idname_with_dot)):
         if not refresh_handled:
             extensions_refresh(