Align CircuitGen Graph with the shared docs layout (ru/en changelog, topic
guides, CodeStyle) and improve bilingual Doxygen in public headers.

- Add docs/ru|en/CHANGELOG.md, GraphML, VerilogImport, Subgraphs,
  TestbenchGenerator; refresh docs hub, README, FUNCTIONALITY, Sequential.
- Expand CodeStyle; normalize “See also” sections.
- Improve bilingual Doxygen (RU terminology, GraphPtr vs VertexPtr, addSequential
  signal order); wrap long comment lines.
- Remove obsolete root CONTRIBUTING/CHANGELOG and legacy docs/BUILDING.md,
  docs/HACKING.md (content lives under docs/ru|en/).
- fix(ci): point lib/lorina submodule at 70707cd (published on origin).