feat(cli): add --version flag

The CLI group had no way to report its version (`openkb version` / `openkb -v`
both fail). Add `@click.version_option(package_name="openkb")` so `openkb
--version` prints "openkb <version>", read from installed package metadata
(tracks the hatch-vcs-derived version, no hardcoded string).

Author: KylinMountain

openkb/cli.py

@@ -757,6 +757,7 @@ def append_cloud_log() -> None:
 
 
 @click.group()
+@click.version_option(package_name="openkb", prog_name="openkb", message="%(prog)s %(version)s")
 @click.option("-v", "--verbose", is_flag=True, default=False, help="Enable verbose logging.")
 @click.option(
     "--kb-dir",

tests/test_cli.py

@@ -9,6 +9,17 @@
 from openkb.schema import AGENTS_MD
 
 
+def test_version_flag_reports_installed_version():
+    import importlib.metadata
+
+    runner = CliRunner()
+    result = runner.invoke(cli, ["--version"])
+    assert result.exit_code == 0
+    # Reports the package's installed version (via importlib.metadata), so it
+    # tracks the hatch-vcs-derived version without a hardcoded string.
+    assert importlib.metadata.version("openkb") in result.output
+
+
 def test_init_creates_structure(tmp_path):
     runner = CliRunner()
     with runner.isolated_filesystem(temp_dir=tmp_path), patch("openkb.cli.register_kb"):