ci: repair lint setup and run it in CI (#15720)

Co-authored-by: Don Isaac <don@bun.sh>

oxlint.json

@@ -0,0 +1,51 @@
+{
+  "$schema": "https://raw.githubusercontent.com/oxc-project/oxc/refs/heads/main/npm/oxlint/configuration_schema.json",
+  "categories": {
+    "correctness": "warn" // TODO: gradually fix bugs and turn this to error
+  },
+  "rules": {
+    "const-comparisons": "off", // TODO: there's a bug when comparing private identifiers. Re-enable once it's fixed.
+    "no-cond-assign": "error",
+    "no-const-assign": "error",
+    "no-debugger": "error",
+    "no-dupe-class-members": "error",
+    "no-dupe-keys": "error",
+    "no-empty-pattern": "error",
+    "import/no-duplicates": "error",
+
+    "no-useless-escape": "off" // there's a lot of these. Should be fixed eventually.
+  },
+  "ignorePatterns": [
+    "vendor",
+    "build",
+    "test/snapshots/**",
+    "bench/react-hello-world/*.js",
+
+    "test/js/node/**/parallel/**",
+    "test/js/node/test/fixtures", // full of JS with intentional syntax errors
+    "test/snippets/**",
+    "test/regression/issue/14477/*.tsx",
+    "test/js/**/*bad.js",
+    "test/bundler/transpiler/decorators.test.ts", // uses `arguments` as decorator
+    "test/bundler/native-plugin.test.ts", // parser doesn't handle import metadata
+    "test/bundler/transpiler/with-statement-works.js" // parser doesn't allow `with` statement
+  ],
+  "overrides": [
+    {
+      "files": ["test/**", "examples/**", "packages/bun-internal/test/runners/**"],
+      "rules": {
+        "no-unused-vars": "off",
+        "no-unused-private-class-members": "off",
+        "no-unnecessary-await": "off"
+      }
+    },
+    {
+      "files": ["test/**", "bench/**"],
+      "rules": {
+        "no-shadow-restricted-names": "off",
+        "no-empty-file": "off",
+        "no-unnecessary-await": "off"
+      }
+    }
+  ]
+}