chore: integrate eslint properly

- Use ESLint in CI
- Upgrade to Flat Configuration
- Fix Codebase of all linting errors and warnings
- Use unused imports plugin

Author: rainerhahnekamp

.eslintignore

@@ -19,6 +19,7 @@ jobs:
           node-version: '18'
           cache: "pnpm"
       - run: pnpm install --frozen-lockfile
+      - run: pnpm run lint:all
       - run: pnpm run test:all
       - run: pnpm run build:all
       - run: ./integration-tests.sh

.eslintrc.json

@@ -1 +1,2 @@
 pnpm lint-staged
+pnpm verify:all

.github/workflows/build.yml

@@ -0,0 +1,29 @@
+const nx = require('@nx/eslint-plugin');
+const baseConfig = require('../../eslint.config.cjs');
+
+module.exports = [
+  ...baseConfig,
+  ...nx.configs['flat/angular'],
+  ...nx.configs['flat/angular-template'],
+  {
+    files: ['**/*.ts'],
+    rules: {
+      '@angular-eslint/directive-selector': [
+        'error',
+        {
+          type: 'attribute',
+          prefix: 'demo',
+          style: 'camelCase',
+        },
+      ],
+      '@angular-eslint/component-selector': [
+        'error',
+        {
+          type: 'element',
+          prefix: 'demo',
+          style: 'kebab-case',
+        },
+      ],
+    },
+  }
+];