Chore: Add ESLint configuration and lint scripts

eslint.config.js

@@ -0,0 +1,84 @@
+import js from "@eslint/js";
+import tseslint from "typescript-eslint";
+import importPlugin from "eslint-plugin-import";
+
+export default tseslint.config(
+  {
+    ignores: [
+      "**/dist/**",
+      "**/node_modules/**",
+      "**/*.d.ts",
+      "**/coverage/**",
+    ],
+  },
+  js.configs.recommended,
+  ...tseslint.configs.recommended,
+  importPlugin.flatConfigs.recommended,
+  importPlugin.flatConfigs.typescript,
+  {
+    languageOptions: {
+      parserOptions: {
+        projectService: true,
+        ecmaVersion: 2020,
+        sourceType: "module",
+      },
+    },
+  },
+  {
+    files: ["**/*.ts", "**/*.tsx"],
+    rules: {
+      // --- Project Conventions ---
+      quotes: ["error", "single", { avoidEscape: true }],
+      "comma-dangle": ["error", "always-multiline"],
+      indent: ["error", 2, { SwitchCase: 1 }],
+
+      // --- TypeScript ---
+      "@typescript-eslint/no-explicit-any": "warn",
+      "@typescript-eslint/explicit-function-return-type": "off",
+      "@typescript-eslint/explicit-module-boundary-types": "off",
+      "@typescript-eslint/no-unused-vars": [
+        "error",
+        { argsIgnorePattern: "^_", varsIgnorePattern: "^_" },
+      ],
+      "@typescript-eslint/consistent-type-imports": [
+        "error",
+        { prefer: "type-imports" },
+      ],
+      "@typescript-eslint/no-non-null-assertion": "warn",
+
+      // --- Import Ordering ---
+      "import/order": [
+        "error",
+        {
+          groups: [
+            "builtin",
+            "external",
+            "internal",
+            "parent",
+            "sibling",
+            "index",
+            "object",
+            "type",
+          ],
+          "newlines-between": "always",
+          alphabetize: { order: "asc", caseInsensitive: true },
+        },
+      ],
+      "import/no-unresolved": "off",
+      "import/no-duplicates": "error",
+
+      // --- General ---
+      "no-console": "warn",
+      "prefer-const": "error",
+      "no-var": "error",
+      eqeqeq: ["error", "always"],
+    },
+  },
+  {
+    files: ["**/*.test.ts", "**/*.spec.ts"],
+    rules: {
+      "no-console": "off",
+      "@typescript-eslint/no-explicit-any": "off",
+    },
+  },
+);

package.json

@@ -6,10 +6,16 @@
     "dev": "pnpm --filter sample-game dev",
     "build": "pnpm --filter boardgame-phaser build && pnpm --filter sample-game build",
     "build:framework": "pnpm --filter boardgame-phaser build",
-    "preview": "pnpm --filter sample-game preview"
+    "preview": "pnpm --filter sample-game preview",
+    "lint": "eslint .",
+    "lint:fix": "eslint . --fix"
   },
   "devDependencies": {
+    "@eslint/js": "^9.17.0",
+    "eslint": "^9.17.0",
+    "eslint-plugin-import": "^2.31.0",
     "typescript": "^5.3.3",
+    "typescript-eslint": "^8.18.0",
     "vitest": "^3.2.4"
   },
   "pnpm": {