feat: add ESLint with TypeScript support for runtime anti-pattern detection

eslint.config.mjs

@@ -0,0 +1,50 @@
+import tsParser from "@typescript-eslint/parser";
+import tsPlugin from "@typescript-eslint/eslint-plugin";
+import nPlugin from "eslint-plugin-n";
+
+export default [
+  {
+    ignores: ["**/node_modules/**", "**/dist/**", "**/.squad/**"],
+  },
+
+  // Source packages — type-aware rules enabled via tsconfig project service
+  {
+    files: ["packages/**/*.ts", "packages/**/*.tsx"],
+    languageOptions: {
+      parser: tsParser,
+      parserOptions: {
+        projectService: true,
+        tsconfigRootDir: import.meta.dirname,
+      },
+    },
+    plugins: {
+      "@typescript-eslint": tsPlugin,
+      n: nPlugin,
+    },
+    rules: {
+      // Catch fire-and-forget promises and missing awaits
+      "@typescript-eslint/no-floating-promises": "warn",
+
+      // Flag synchronous I/O inside functions (allowAtRootLevel
+      // permits sync calls in module-level config/setup code)
+      "n/no-sync": ["warn", { allowAtRootLevel: true }],
+
+      // Prevent console.log in production; allow warn/error
+      "no-console": ["warn", { allow: ["warn", "error"] }],
+    },
+  },
+
+  // Test files — no tsconfig coverage, so only non-type-aware rules
+  {
+    files: ["test/**/*.ts"],
+    languageOptions: {
+      parser: tsParser,
+    },
+    plugins: {
+      "@typescript-eslint": tsPlugin,
+    },
+    rules: {
+      "no-console": ["warn", { allow: ["warn", "error"] }],
+    },
+  },
+];