HDDS-14602. Bump pnpm to 10.28.2, Node.js to 20.18.2

[arunsarin85]

What changes were proposed in this pull request?

Upgraded the pnpm package manager used by the Recon web UI build from v8.15.7 to v10.28.2 (latest stable).

pnpm v8 reached end-of-life in 2024 and is no longer receiving security or bug fixes. This upgrade moves the project to a supported release.

The following files were updated:

• hadoop-ozone/recon/pom.xml - bumped pnpm.version property from 8.15.7 to 10.28.2, used by frontend-maven-plugin to install pnpm during the Maven build.
• ozone-recon-web/package.json - updated packageManager field to pnpm@10.28.2; added pnpm.onlyBuiltDependencies to explicitly allow @swc/core and esbuild to run their postinstall scripts (required by pnpm v10's new security model for build scripts).
• pom.xml (root) - bumped nodejs.version from 16.14.2 to 20.18.2. pnpm v10 requires Node.js ≥ v18.12; Node.js v20.x is the current Active LTS release and satisfies this requirement.
• pnpm-lock.yaml - regenerated with pnpm v10.28.2; lockfile format updated from version 6.0 (pnpm v8) to 9.0 (pnpm v10).

What is the link to the Apache JIRA

https://issues.apache.org/jira/browse/HDDS-14602

How was this patch tested?

• Ran pnpm install with pnpm v10.28.2 - completed successfully with no errors.
• Ran pnpm build (vite build) - build completed successfully, generating all output bundles.
• Ran the full Maven build for the ozone - pnpm v10.28.2 is correctly downloaded and used by frontend-maven-plugin with Node.js v20.18.2.

[adoroszlai]

@spacemonkd please take a look