Refactor UI assets and harden quality checks

pyproject.toml

@@ -55,8 +55,12 @@ line-length = 120
 target-version = "py311"
 
 [tool.ruff.lint]
-select = ["E", "F", "I", "UP", "B"]
-ignore = ["E501"]
+select = ["E", "F", "I", "UP", "B", "ANN"]
+ignore = ["ANN401"]
+
+[tool.ruff.lint.per-file-ignores]
+"scripts/build-bootstrap-subset.py" = ["E501"]
+"tests/**/*.py" = ["ANN"]
 
 [tool.black]
 line-length = 120