fix: all lint errors, test + lint pre-commit passing

Frontend:
- Split nodeTypes/edgeTypes into separate .ts files (react-refresh)
- Remove setState-in-effect in NodeModal (key prop reset)
- Fix handleSave accessed before declaration (useRef pattern)
- Exclude src/components/ui/** from eslint (shadcn generated)
- Use defineConfig from vitest/config for test type support

Backend:
- ruff --fix: sort imports, datetime.UTC alias
- Raise line-length to 120, ignore E501 in tests
- Break long update_node/update_edge signatures
- pyproject.toml: per-file-ignores for tests

frontend/eslint.config.js

@@ -6,7 +6,7 @@ import tseslint from 'typescript-eslint'
 import { defineConfig, globalIgnores } from 'eslint/config'
 
 export default defineConfig([
-  globalIgnores(['dist']),
+  globalIgnores(['dist', 'src/components/ui/**']),
   {
     files: ['**/*.{ts,tsx}'],
     extends: [