fix(npm): use original node regex in npm resolution

cli/tests/testdata/npm/conditional_exports/main.js

@@ -1,10 +1,12 @@
 import mod from "npm:@denotest/conditional-exports";
+import foo from "npm:@denotest/conditional-exports/foo.js";
 import client from "npm:@denotest/conditional-exports/client";
 import clientFoo from "npm:@denotest/conditional-exports/client/foo";
 import clientBar from "npm:@denotest/conditional-exports/client/bar";
 import supportsESM from "npm:supports-esm";
 
 console.log(mod);
+console.log(foo);
 console.log(client);
 console.log(clientFoo);
 console.log(clientBar);

cli/tests/testdata/npm/conditional_exports/main.out

@@ -7,6 +7,7 @@ Download http://localhost:4545/npm/registry/@ljharb/has-package-exports-patterns
 Download http://localhost:4545/npm/registry/has-package-exports/has-package-exports-1.3.0.tgz
 Download http://localhost:4545/npm/registry/supports-esm/supports-esm-1.0.0.tgz
 { hello: "from esm" }
+{ hello: "from foo" }
 { hello: "from esm client" }
 { hello: "from esm client foo" }
 { hello: "from esm client bar" }

cli/tests/testdata/npm/registry/@denotest/conditional-exports/1.0.0/foo.js

@@ -0,0 +1,3 @@
+export default {
+  hello: "from foo",
+}

cli/tests/testdata/npm/registry/@denotest/conditional-exports/1.0.0/package.json

@@ -15,6 +15,7 @@
     "./client/*": {
       "types": "./types/src/client/*.d.ts",
       "import": "./esm/client/*.js"
-    }
+    },
+    "./*": "./*"
   }
 }

ext/node/resolution.rs

@@ -339,7 +339,7 @@ fn resolve_package_target_string(
     ));
   }
   let invalid_segment_re =
-    Regex::new(r"(^|\|/)(..?|node_modules)(\|/|$)").expect("bad regex");
+    Regex::new(r"(^|\\|/)(\.\.?|node_modules)(\\|/|$)").expect("bad regex");
   let pattern_re = Regex::new(r"\*").expect("bad regex");
   if !target.starts_with("./") {
     if internal && !target.starts_with("../") && !target.starts_with('/') {