run the whole suite from runtest.sh

It invoked pytest on test_wiki_diff_matcher.py alone, so it exercised 19
of the 69 tests despite its name, and it required uv, which contradicts
the README's statement that uv is optional.

Point it at test/ and use whichever python is on the path. It cds to the
repository root first, since several tests open fixture files by paths
relative to it, and passes any extra arguments through.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
(cherry picked from commit 7fff65c23d7c7a2868abccb235ec376fe093d4c1)

runtest.sh

@@ -1,2 +1,6 @@
 #!/usr/bin/env bash
-uv run pytest test/test_wiki_diff_matcher.py --capture=tee-sys
+# Run the test suite from the repository root, which some tests require
+# because they open fixture files by relative path.
+set -euo pipefail
+cd "$(dirname "$0")"
+exec python -m pytest test/ "$@"