feat(cli): add aggregate output format options for docs parity

The README/CONTRIBUTING examples used `obliteratus aggregate --format ...` but the CLI only accepted `--dir`.
This adds `--format {summary,latex}`, `--metric`, and `--min-runs` to the aggregate command, reuses community LaTeX table generation, and adds CLI parsing tests to align behavior with documented usage.

tests/test_cli.py

@@ -101,6 +101,29 @@ class TestCLIDispatch:
         )
         assert "no contributions found" in printed_text.lower() or mock_console.print.called
 
+    def test_aggregate_accepts_format_metric_min_runs(self):
+        """aggregate accepts --format, --metric and --min-runs flags."""
+        with patch("obliteratus.cli._cmd_aggregate") as mock_cmd:
+            main([
+                "aggregate",
+                "--format", "latex",
+                "--metric", "refusal_rate",
+                "--min-runs", "3",
+            ])
+            mock_cmd.assert_called_once()
+            args_passed = mock_cmd.call_args[0][0]
+            assert args_passed.format == "latex"
+            assert args_passed.metric == "refusal_rate"
+            assert args_passed.min_runs == 3
+
+    def test_aggregate_rejects_invalid_format(self):
+        """aggregate rejects unknown --format choices."""
+        stderr_text = _capture_exit(
+            ["aggregate", "--format", "invalid"],
+            expect_code=2,
+        )
+        assert "invalid choice" in stderr_text.lower()
+
     # 7. --help flag prints help
     def test_help_flag(self):
         """Calling main(['--help']) should print help and exit 0."""