devcontainer, proper CI/CD, etc etc

eslint.config.js

@@ -0,0 +1,26 @@
+import js from '@eslint/js';
+import prettier from 'eslint-config-prettier';
+
+export default [
+  {
+    files: ['src/**/*.js'],
+    ...js.configs.recommended,
+    languageOptions: {
+      ecmaVersion: 'latest',
+      sourceType: 'script',
+      globals: {
+        document: 'readonly',
+        window: 'readonly',
+        localStorage: 'readonly',
+        console: 'readonly',
+        fetch: 'readonly',
+        Image: 'readonly',
+        CustomEvent: 'readonly',
+      },
+    },
+    rules: {
+      'no-unused-vars': ['warn', { argsIgnorePattern: '^_' }],
+    },
+  },
+  prettier,
+];