Add quick-start help command

tests/test_cli_help.py

@@ -0,0 +1,11 @@
+from __future__ import annotations
+
+from scimesh.cli import main
+
+
+def test_help_command_prints_runnable_examples(capsys: object) -> None:
+    assert main(["help"]) == 0
+    output = capsys.readouterr().out
+    assert "scimesh similarity-search" in output
+    assert "scimesh similarity-graph" in output
+    assert "mkdir -p results" in output