Add linter for web folder

web/eslint.config.mjs

@@ -0,0 +1,55 @@
+export default [
+    {
+        files: ['src/**/*.js'],
+        ignores: ['src/js/wasm_exec.js'],
+        languageOptions: {
+            ecmaVersion: 2022,
+            sourceType: 'module',
+            globals: {
+                // Browser globals
+                window: 'readonly',
+                document: 'readonly',
+                console: 'readonly',
+                fetch: 'readonly',
+                URL: 'readonly',
+                Blob: 'readonly',
+                Uint8Array: 'readonly',
+                TextEncoder: 'readonly',
+                TextDecoder: 'readonly',
+                Event: 'readonly',
+                DOMException: 'readonly',
+                HTMLElement: 'readonly',
+                Worker: 'readonly',
+                requestAnimationFrame: 'readonly',
+                // JSZip loaded via script tag
+                JSZip: 'readonly',
+            },
+        },
+        rules: {
+            'no-unused-vars': ['warn', { argsIgnorePattern: '^_' }],
+            'no-undef': 'error',
+            'no-constant-condition': 'warn',
+            'eqeqeq': ['error', 'always'],
+            'no-var': 'error',
+            'prefer-const': 'warn',
+        },
+    },
+    {
+        // Worker script uses importScripts, self, Go, globalThis, WebAssembly
+        files: ['src/js/patch-worker.js'],
+        languageOptions: {
+            globals: {
+                self: 'readonly',
+                importScripts: 'readonly',
+                Go: 'readonly',
+                globalThis: 'readonly',
+                WebAssembly: 'readonly',
+                fetch: 'readonly',
+                console: 'readonly',
+            },
+        },
+    },
+    {
+        ignores: ['src/js/wasm_exec.js', 'dist/**', 'node_modules/**'],
+    },
+];