Organize tools and move Python tests into tools/tests

tools/tests/README.md

@@ -0,0 +1,25 @@
+# Python Tooling Tests
+
+Unit tests for the scripts in `tools/`. They use the standard library
+`unittest` plus Pillow; no Godot or Blender process is started.
+
+Run them from the repository root:
+
+```bash
+python3 -m pip install -r requirements-tools.txt
+python3 -m unittest discover -s tools/tests -t tools -p 'test_*.py'
+```
+
+The `-t tools` top-level directory is required: the tests import the tool
+modules by their plain names (for example `import blender_assets`).
+
+Individual example:
+
+```bash
+python3 -m unittest tools.tests.test_model_review -v
+```
+
+(Module-style invocation requires `tools/tests/__init__.py`, which is committed.)
+
+These tests do not call OpenRouter. The judge/image tests mock the HTTP layer;
+live generation and judging remain manual, development-only operations.