Configure ESLint with Prettier and TypeScript support.

- Baseline existing errors to warnings.
- Fix Image to PDF tool for HEIC and WebP inputs.
- Apply linting auto-fixes.

eslint.config.mjs

@@ -0,0 +1,47 @@
+import globals from "globals";
+import pluginJs from "@eslint/js";
+import tseslint from "typescript-eslint";
+import eslintConfigPrettier from "eslint-config-prettier";
+
+export default [
+    { files: ["**/*.{js,mjs,cjs,ts}"] },
+    { ignores: ["dist/**", "coverage/**", "node_modules/**", "**/.vitepress/cache/**", "public/**/*.min.js"] },
+    { languageOptions: { globals: { ...globals.browser, ...globals.node } } },
+    pluginJs.configs.recommended,
+    ...tseslint.configs.recommended,
+    eslintConfigPrettier,
+    {
+        rules: {
+            "@typescript-eslint/no-explicit-any": "warn",
+            "@typescript-eslint/no-unused-vars": ["warn", { "argsIgnorePattern": "^_" }],
+            "@typescript-eslint/no-unused-expressions": "warn",
+            "no-redeclare": "warn",
+            "no-constant-condition": "warn",
+            "no-ex-assign": "warn",
+            "no-empty": "warn",
+            "no-case-declarations": "warn",
+            "@typescript-eslint/no-this-alias": "warn",
+            "no-func-assign": "warn",
+            "no-fallthrough": "warn",
+            "no-cond-assign": "warn",
+            "no-irregular-whitespace": "warn",
+            "no-prototype-builtins": "warn",
+            "no-undef": "warn",
+            "no-useless-escape": "warn",
+            "no-unsafe-finally": "warn",
+            "no-self-assign": "warn",
+            "no-control-regex": "warn",
+            "@typescript-eslint/no-require-imports": "warn",
+            "getter-return": "warn",
+            "no-constant-binary-expression": "warn",
+            "@typescript-eslint/ban-ts-comment": "warn",
+            "no-unused-private-class-members": "warn",
+            "no-unreachable": "warn",
+            "no-setter-return": "warn",
+            "no-useless-catch": "warn",
+            "valid-typeof": "warn",
+            "no-sparse-arrays": "warn",
+            "no-misleading-character-class": "warn"
+        }
+    }
+];