chore: configure code quality tools

Add EditorConfig for consistent editor settings, Prettier for formatting (4-space indentation), ESLint with TypeScript rules, and linting documentation

eslint.config.mjs

@@ -0,0 +1,134 @@
+// @ts-check
+import eslint from '@eslint/js';
+import eslintPluginPrettierRecommended from 'eslint-plugin-prettier/recommended';
+import globals from 'globals';
+import tseslint from 'typescript-eslint';
+
+export default tseslint.config(
+    {
+        ignores: [
+            'eslint.config.mjs',
+            '**/dist/**',
+            '**/node_modules/**',
+            '**/coverage/**',
+            '**/.puaros/**',
+            '**/build/**',
+        ],
+    },
+    eslint.configs.recommended,
+    ...tseslint.configs.strictTypeChecked,
+    ...tseslint.configs.stylisticTypeChecked,
+    eslintPluginPrettierRecommended,
+    {
+        languageOptions: {
+            globals: {
+                ...globals.node,
+                ...globals.jest,
+                ...globals.es2021,
+            },
+            sourceType: 'commonjs',
+            parserOptions: {
+                projectService: true,
+                tsconfigRootDir: import.meta.dirname,
+            },
+        },
+    },
+    {
+        rules: {
+            // ========================================
+            // TypeScript Best Practices
+            // ========================================
+            '@typescript-eslint/no-explicit-any': 'warn', // Warn about 'any' usage
+            '@typescript-eslint/no-unsafe-assignment': 'warn',
+            '@typescript-eslint/no-unsafe-member-access': 'warn',
+            '@typescript-eslint/no-unsafe-call': 'warn',
+            '@typescript-eslint/no-unsafe-return': 'warn',
+            '@typescript-eslint/no-unsafe-argument': 'warn',
+            '@typescript-eslint/explicit-function-return-type': [
+                'warn',
+                {
+                    allowExpressions: true,
+                    allowTypedFunctionExpressions: true,
+                    allowHigherOrderFunctions: true,
+                },
+            ],
+            '@typescript-eslint/explicit-module-boundary-types': 'warn',
+            '@typescript-eslint/no-unused-vars': [
+                'error',
+                {
+                    argsIgnorePattern: '^_',
+                    varsIgnorePattern: '^_',
+                    caughtErrorsIgnorePattern: '^_',
+                },
+            ],
+            '@typescript-eslint/no-floating-promises': 'error',
+            '@typescript-eslint/await-thenable': 'error',
+            '@typescript-eslint/no-misused-promises': 'error',
+            '@typescript-eslint/prefer-nullish-coalescing': 'warn',
+            '@typescript-eslint/prefer-optional-chain': 'warn',
+            '@typescript-eslint/prefer-readonly': 'warn',
+            '@typescript-eslint/promise-function-async': 'warn',
+            '@typescript-eslint/require-await': 'warn',
+            '@typescript-eslint/no-unnecessary-condition': 'warn',
+            '@typescript-eslint/no-non-null-assertion': 'warn',
+
+            // ========================================
+            // Code Quality & Best Practices
+            // ========================================
+            'no-console': ['warn', { allow: ['warn', 'error'] }],
+            'no-debugger': 'error',
+            'no-alert': 'error',
+            'no-var': 'error',
+            'prefer-const': 'error',
+            'prefer-arrow-callback': 'warn',
+            'prefer-template': 'warn',
+            'no-nested-ternary': 'warn',
+            'no-unneeded-ternary': 'error',
+            'no-else-return': 'warn',
+            eqeqeq: ['error', 'always'],
+            curly: ['error', 'all'],
+            'no-multiple-empty-lines': ['error', { max: 1, maxEOF: 0 }],
+            'no-trailing-spaces': 'error',
+            'comma-dangle': ['error', 'always-multiline'],
+
+            // ========================================
+            // Code Style (handled by Prettier mostly)
+            // ========================================
+            indent: ['error', 4, { SwitchCase: 1 }],
+            '@typescript-eslint/indent': 'off', // Let Prettier handle this
+            quotes: ['error', 'single', { avoidEscape: true }],
+            semi: ['error', 'always'],
+
+            // ========================================
+            // Prettier Integration
+            // ========================================
+            'prettier/prettier': [
+                'error',
+                {
+                    tabWidth: 4,
+                    endOfLine: 'auto',
+                },
+            ],
+
+            // ========================================
+            // Complexity & Maintainability
+            // ========================================
+            complexity: ['warn', 15],
+            'max-depth': ['warn', 4],
+            'max-lines-per-function': ['warn', { max: 100, skipBlankLines: true, skipComments: true }],
+            'max-params': ['warn', 5],
+
+            // ========================================
+            // Imports & Dependencies
+            // ========================================
+            'no-duplicate-imports': 'error',
+            'sort-imports': [
+                'warn',
+                {
+                    ignoreCase: true,
+                    ignoreDeclarationSort: true,
+                },
+            ],
+        },
+    },
+);