feat(eslint): add eslint flat config

.eslint/jsx-a11y.ts

@@ -0,0 +1,31 @@
+import type { Linter } from "eslint";
+// @ts-expect-error - no types available
+import jsxA11y from "eslint-plugin-jsx-a11y";
+import { astroFiles, javascriptFiles, typescriptFiles } from "./shared";
+
+export const jsxA11yConfig: Linter.Config = {
+  name: "eslint/jsx-a11y",
+  files: [
+    ...astroFiles,
+    ...typescriptFiles.filter((f) => f.includes("tsx")),
+    ...javascriptFiles.filter((f) => f.includes("jsx")),
+  ],
+  plugins: {
+    "jsx-a11y": jsxA11y,
+  },
+  rules: {
+    ...jsxA11y.configs.recommended.rules,
+
+    // Additional a11y rules
+    "jsx-a11y/alt-text": "error",
+    "jsx-a11y/anchor-has-content": "error",
+    "jsx-a11y/anchor-is-valid": "error",
+    "jsx-a11y/click-events-have-key-events": "error",
+    "jsx-a11y/interactive-supports-focus": "error",
+    "jsx-a11y/no-redundant-roles": "error",
+    "jsx-a11y/img-redundant-alt": "error",
+    "jsx-a11y/no-access-key": "error",
+    "jsx-a11y/label-has-associated-control": "error",
+    "jsx-a11y/no-autofocus": "warn",
+  },
+};