[javascript] Bump Node.js from v26.4.0 to v26.5.0

[hayat01sh1da]

1. Overview

This Pull Request bumps Node.js from v26.4.0 to v26.5.0 across the repository.
Alongside the runtime bump, pnpm is updated from 11.9.0 to 11.13.0 in the JavaScript exercises' documentation and manifest.
The version pin in .node-version, the supported-versions table in SECURITY.md, and the JavaScript environment docs are all kept in sync with the new toolchain.

2. Key Changes & Differences

Files	Before	After	Changes & Differences
.node-version	v26.4.0	v26.5.0	Bumped the repository-wide Node.js version pin.
SECURITY.md	JavaScript exercises: Node v26.4.0	JavaScript exercises: Node v26.5.0	Updated the supported-versions table to reflect the new Node.js version.
javascript/README.md	Node v26.4.0 / pnpm 11.9.0	Node v26.5.0 / pnpm 11.13.0	Updated the environment section with the new Node.js and pnpm versions.
javascript/package.json	Node.js v26.4.0 / pnpm 11.9.0 in description	Node.js v26.5.0 / pnpm 11.13.0 in description	Synced the environment description with the new toolchain versions.

3. Summary

• Bumped Node.js from v26.4.0 to v26.5.0 via .node-version.
• Bumped pnpm from 11.9.0 to 11.13.0 in the JavaScript exercises' documentation and manifest.
• Kept SECURITY.md, javascript/README.md, and javascript/package.json in sync with the new toolchain versions.
• No source code or dependency changes are included; this is a toolchain/documentation-only update.

4. References

• .node-version
• SECURITY.md
• javascript/README.md
• javascript/package.json
• Node.js v26.5.0 Release Notes
• pnpm Releases

[hayat01sh1da]