docs: set version 2.3.1 as default and fix internal links

- Changed lastVersion from "current" to "2.3.1" to make the stable
  version the default when users visit the documentation site
- Updated internal links in Interactive-Tools to use version-agnostic
  paths (/docs/Introduction instead of /docs/2.3.1/Introduction)
- Blog posts are already correctly sorted with latest first (Nov 13 → Nov 8)

This ensures users land on the stable 2.3.1 documentation by default
while keeping Next (2.4.0-dev) available via the version dropdown.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: github-actions[bot]

docs-site/docusaurus.config.js

@@ -182,7 +182,7 @@ const config = {
       {
         docs: {
           sidebarPath: "./sidebars.js",
-          lastVersion: "current",
+          lastVersion: "2.3.1",
           versions: {
             current: {
               label: "2.4.0-dev (Next)",

docs-site/versioned_docs/version-2.3.1/Interactive-Tools.mdx

@@ -36,7 +36,7 @@ import PerformanceCalculator from "@site/src/components/PerformanceCalculator";
 
 ## Additional Resources
 
-- [Getting Started Guide](/docs/2.3.1/Introduction)
-- [API Reference](/docs/2.3.1/API-Reference)
-- [Deployment Guides](/docs/2.3.1/Deployment-Docker)
-- [Performance Optimization](/docs/2.3.1/Performance)
+- [Getting Started Guide](/docs/Introduction)
+- [API Reference](/docs/API-Reference)
+- [Deployment Guides](/docs/Deployment-Docker)
+- [Performance Optimization](/docs/Performance)