docs(RMGR-WP-0001): complete T04 implementation foundation

Accept ADR-001: Python 3.12, FastAPI, Postgres/SQLAlchemy async, src layout,
uv/hatchling, pytest. Scaffold package, rmgr CLI stub, and version tests.

tests/test_version.py

@@ -0,0 +1,11 @@
+from repo_manager import __version__
+from repo_manager.cli import main
+
+
+def test_version_string():
+    assert __version__ == "0.1.0"
+
+
+def test_cli_version(capsys):
+    assert main(["--version"]) == 0
+    assert "0.1.0" in capsys.readouterr().out