implement pnpm migration (#22262)

### What does this PR do?

fixes #7157, fixes #14662

migrates pnpm-workspace.yaml data to package.json & converts
pnpm-lock.yml to bun.lock

---

### How did you verify your code works?

manually, tests and real world examples

---------

Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>
Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: Dylan Conway <dylan.conway567@gmail.com>

src/install/PackageManager/WorkspacePackageJSONCache.zig

@@ -78,8 +78,6 @@ pub fn getWithPath(
         },
     ) catch |err| {
         _ = this.map.remove(key);
-        allocator.free(source.contents);
-        allocator.free(key);
         bun.handleErrorReturnTrace(err, @errorReturnTrace());
         return .{ .parse_err = err };
     };