chore: repoint legacy repository URLs (org migration 2026-09-22)

[ActInfInstitute]

Summary

Repoints legacy repository URLs after the 2026-09-22 org migration (ActInfInstitute → ActiveInferenceInstitute, renamed repos). Old URLs redirect; this makes references canonical.

Replacements (13 lines, 10 files)

All: github.com/ActiveInferenceInstitute/GeneralizedNotationNotation → github.com/ActiveInferenceInstitute/Generalized_Notation_Notation

• cogant/docs/evaluation/GNN_VALIDATION_REPORT.md:17-19
• cogant/examples/demo_server.py:77
• cogant/py/cogant/init.py:6
• cogant/py/cogant/schemas/gnn_export.py:5
• cogant/pyproject.toml:67 (git+ dependency URL, pin rev unchanged)
• cogant/rust/cogant-gnn/src/lib.rs:4
• cogant/tests/unit/test_gnn_spec_compliance.py:10
• cogant/uv.lock:474,1190 (git source URLs, rev unchanged)
• manuscript/01_introduction.md:9
• manuscript/references.bib:369

Left unchanged: prose mentions of "GeneralizedNotationNotation" (release-bundle names, package descriptions) per migration policy; placeholder local path --target /path/to/GeneralizedNotationNotation/src in docs.

Governance: https://github.com/ActiveInferenceInstitute/nest-internal/blob/main/governance/github-org-migration.md