Update eslint to 9 and add jsdoc plugin

- Update eslint from 8 to 9.
- Migrate the old config to the new eslint flat configs
- Add eslint-plugin-jsdoc to check jsdoc validity and prevent false positives of "no-unused-vars" when importing a type only for jsdoc.
- Fix all new errors and warnings
- Fix "ComponentScope.test.tsx" that didn't check for React strict mode

Author: Wendystraite

.eslintrc.json

@@ -0,0 +1,69 @@
+import { defineConfig } from "eslint/config";
+import tseslint from "typescript-eslint";
+import globals from "globals";
+import jsdoc from "eslint-plugin-jsdoc";
+
+export default defineConfig(
+  {
+    // Global ignores - files/directories to ignore
+    ignores: [
+      "**/examples/**",
+      "**/dist/**",
+      "**/node_modules/**",
+      "**/website/**",
+      "**/coverage/**",
+    ],
+  },
+  // Apply recommended configs
+  tseslint.configs.recommended,
+  jsdoc.configs["flat/recommended"],
+  jsdoc.configs["flat/recommended-typescript"],
+  {
+    // Configuration for all files
+    files: ["**/*.js", "**/*.ts", "**/*.tsx"],
+    plugins: { jsdoc },
+    languageOptions: {
+      ecmaVersion: "latest",
+      sourceType: "module",
+      globals: {
+        ...globals.browser,
+        ...globals.node,
+      },
+    },
+    rules: {
+      // Disable overly strict JSDoc rules
+      "jsdoc/require-jsdoc": "off",
+      "jsdoc/require-param": "off",
+      "jsdoc/require-returns": "off",
+      "jsdoc/tag-lines": "off",
+      // Checks that types in jsdoc comments are defined.
+      "jsdoc/no-undefined-types": "error",
+      // Add @typeParam tag support
+      "jsdoc/check-tag-names": ["warn", { definedTags: ["typeParam"] }],
+      // TypeScript unused vars - allow underscore prefix
+      "@typescript-eslint/no-unused-vars": [
+        "error",
+        {
+          argsIgnorePattern: "^_",
+          varsIgnorePattern: "^_",
+          caughtErrorsIgnorePattern: "^_",
+        },
+      ],
+    },
+  },
+  {
+    // Configuration for test files
+    files: ["src/**/*.test.{ts,tsx}", "src/**/testing/**/*.{ts,tsx}"],
+    rules: {
+      "@typescript-eslint/no-explicit-any": "off",
+      "@typescript-eslint/no-non-null-assertion": "off",
+    },
+  },
+  {
+    // Configuration for benchmark files
+    files: ["src/**/*.bench.{ts,tsx}"],
+    rules: {
+      "@typescript-eslint/no-unused-vars": "off",
+    },
+  },
+);