fix: refuse to scaffold prj- repos from statehub register

STATE-WP-0080-T01: detect project flavor from classification, GOAL.md,
or a prj- slug, then exit pointing at rmgr scaffold. Durable-repo
write path is unchanged. Rebind 0080 hub IDs to the live workstream
and open T02 now that RMGR-WP-0004-T03 has landed.

tests/test_statehub_register_cli.py

@@ -11,6 +11,9 @@ import custodian_cli
 from custodian_cli import cmd_fix_consistency
 from statehub_register import (
     RegisterInference,
+    detect_project_flavor_signal,
+    refuse_project_flavor_scaffold,
+    run_register,
     _invoke_llm,
     _normalise_inference,
     _parse_json_object,
@@ -101,6 +104,107 @@ def test_write_registration_files_primes_codex_repo(tmp_path: Path):
     assert "statehub fix-consistency" in workplan
 
 
+def test_detect_project_flavor_from_classification(tmp_path: Path):
+    (tmp_path / ".repo-classification.yaml").write_text(
+        "repo_classification:\n  category: project\n  domain: infotech\n",
+        encoding="utf-8",
+    )
+
+    assert detect_project_flavor_signal(tmp_path) == (
+        ".repo-classification.yaml category=project"
+    )
+
+
+def test_detect_project_flavor_from_goal_md(tmp_path: Path):
+    (tmp_path / "GOAL.md").write_text(
+        "---\nrepo_flavor: project\n---\n\n# Project goal\n",
+        encoding="utf-8",
+    )
+
+    assert detect_project_flavor_signal(tmp_path) == "GOAL.md repo_flavor=project"
+
+
+def test_detect_project_flavor_from_prj_directory_name(tmp_path: Path):
+    repo = tmp_path / "prj-example"
+    repo.mkdir()
+
+    assert detect_project_flavor_signal(repo) == "slug prefix prj- (prj-example)"
+
+
+def test_detect_project_flavor_from_repo_slug_argument(tmp_path: Path):
+    repo = tmp_path / "example"
+    repo.mkdir()
+
+    assert detect_project_flavor_signal(repo) is None
+    assert detect_project_flavor_signal(repo, "prj-example") == (
+        "slug prefix prj- (prj-example)"
+    )
+
+
+def test_classification_project_takes_precedence_over_slug(tmp_path: Path):
+    repo = tmp_path / "prj-example"
+    repo.mkdir()
+    (repo / ".repo-classification.yaml").write_text(
+        "repo_classification:\n  category: project\n  domain: infotech\n",
+        encoding="utf-8",
+    )
+
+    assert detect_project_flavor_signal(repo) == (
+        ".repo-classification.yaml category=project"
+    )
+
+
+def test_durable_repo_is_not_project_flavor(tmp_path: Path):
+    (tmp_path / ".repo-classification.yaml").write_text(
+        "repo_classification:\n  category: tooling\n  domain: infotech\n",
+        encoding="utf-8",
+    )
+
+    assert detect_project_flavor_signal(tmp_path, "demo-service") is None
+
+
+def test_refuse_project_flavor_scaffold_points_at_rmgr(tmp_path: Path):
+    repo = tmp_path / "prj-example"
+    repo.mkdir()
+
+    with pytest.raises(SystemExit, match="rmgr scaffold") as exc:
+        refuse_project_flavor_scaffold(repo)
+
+    message = str(exc.value)
+    assert "refuses to scaffold a project-flavor repository" in message
+    assert "never PRJ-WP-" in message
+    assert str(repo) in message
+
+
+def test_run_register_refuses_prj_repo_without_writing_or_calling_api(
+    tmp_path: Path, monkeypatch: pytest.MonkeyPatch
+):
+    repo = tmp_path / "prj-example"
+    repo.mkdir()
+    (repo / ".repo-classification.yaml").write_text(
+        "repo_classification:\n  category: project\n  domain: infotech\n",
+        encoding="utf-8",
+    )
+    called: list[str] = []
+    monkeypatch.setattr(
+        "statehub_register._check_api",
+        lambda *_args, **_kwargs: called.append("api"),
+    )
+    monkeypatch.setattr(
+        "statehub_register.write_registration_files",
+        lambda **_kwargs: called.append("write") or [],
+    )
+
+    args = argparse.Namespace(path=str(repo), repo_slug=None)
+
+    with pytest.raises(SystemExit, match="rmgr scaffold"):
+        run_register(args)
+
+    assert called == []
+    assert not (repo / "INTENT.md").exists()
+    assert not (repo / "workplans").exists()
+
+
 def test_write_registration_files_is_idempotent_without_force(tmp_path: Path):
     inference = RegisterInference()
     kwargs = {