fix(minifier): mangle class private members in Node API (#26118)

## Summary

Fixes #26097.

The minify function did not work on class private fields，because their
mappings were not forwarded to codegen:

```rs
class Foo {
  #privateField = 1;

  method() {
    return this.#privateField;
  }
}
```

And this PR is to make it match what's expected:

```rs
class Foo {
  #e = 1;

  method() {
    return this.#e;
  }
}
```

napi/minify/src/lib.rs

@@ -93,6 +93,7 @@ fn minify_impl(filename: &str, source_text: &str, options: Option<MinifyOptions>
 
     let minifier_ret = Minifier::new(minifier_options).minify(&allocator, &mut program);
     let scoping = minifier_ret.scoping;
+    let class_private_mappings = minifier_ret.class_private_mappings;
     let mangle_cache = parser_ret
         .diagnostics
         .is_empty()
@@ -122,7 +123,11 @@ fn minify_impl(filename: &str, source_text: &str, options: Option<MinifyOptions>
         codegen_options.source_map_path = Some(PathBuf::from(&filename));
     }
 
-    let ret = Codegen::new().with_options(codegen_options).with_scoping(scoping).build(&program);
+    let ret = Codegen::new()
+        .with_options(codegen_options)
+        .with_scoping(scoping)
+        .with_private_member_mappings(class_private_mappings)
+        .build(&program);
 
     let legal_comments =
         ret.legal_comments.iter().map(|c| c.span.source_text(source_text).to_string()).collect();

napi/minify/test/minify.test.ts

@@ -140,6 +140,19 @@ describe("async minify", () => {
   });
 });
 
+describe("identifier mangling", () => {
+  it("mangles class private members", () => {
+    const ret = minifySync(
+      "test.js",
+      "class Foo { #privateField = 1; method() { return this.#privateField; } }",
+      { compress: false, mangle: true },
+    );
+
+    expect(ret.errors).toHaveLength(0);
+    expect(ret.code).toBe("class Foo{#e=1;method(){return this.#e}}");
+  });
+});
+
 describe("property mangling", () => {
   it("is independent from identifier mangling and returns a reusable cache", () => {
     const ret = minifySync("test.js", "let local; obj._often; obj._rare; obj._often;", {