docs: make the change ready for upstream review

Remove personal names, local paths and fork-only process notes from code comments,
docs and the plugin manifest (repository now points at the upstream project), and
drop the handoff section from the plan.

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

plugins/opencad-python/plugin.toml

@@ -5,7 +5,7 @@ version = "0.1.0"
 description = "Embedded Python scripting (RustPython) for Open CAD Studio."
 author = "Felix Riestra"
 license = "GPL-3.0-only"
-repository = "felixriestra/OpenCADStudio"
+repository = "HakanSeven12/OpenCADStudio"
 
 [opencad]
 api_version = 7