Point the package metadata and READMEs at docs.arcadedb.com/arcadedb-python, now that it is live #120

The docs are live at https://docs.arcadedb.com/arcadedb-python/ since ArcadeData/arcadedb-docs#505 was merged on 2026-10-28 (all component pages return 200). The repository still points readers at the old site: pyproject.toml Documentation = "https://docs.humem.ai/arcadedb/", a README bullet that says the component is not published yet, another to docs.humem.ai, three links in examples/README.md, two in tests/README.md, and comments in docs.yml and docs/antora-playbook.yml. The repo homepage is empty.