Add missing tools directory

tools/generate_requirements_txt.py

@@ -0,0 +1,19 @@
+from __future__ import annotations
+
+from pathlib import Path
+
+import tomllib
+
+this_script = Path(__file__)
+root = this_script.parents[1]
+pyproject = root / 'pyproject.toml'
+
+with open(pyproject, 'rb') as f:
+    metadata = tomllib.load(f)
+    dependencies = metadata['project']['dependencies']
+
+with open('requirements.txt', 'w') as f:
+    this_script_rel = this_script.relative_to(root)
+    f.write(f'# generated by {this_script_rel}\n')
+    f.write('\n'.join(dependencies))
+    f.write('\n')