Stop publishing stale v1 and v2 docs

[Lovlace777]

Description

Summary

• Stops downloading Fastify v1 and v2 docs during website builds.
• Skips v1 and v2 release folders during release processing, including when cached release data is restored in CI.
• Keeps currently published v3, v4, and v5 docs generation unchanged.

Validation

• npm ci passed.
• npm run lint:js passed.
• npm run lint:style passed.
• node --check scripts/process-releases.js passed.
• git diff --cached --check passed.
• PowerShell content check confirmed the v1/v2 download commands are absent.
• npm run format:check did not pass locally because the current Windows checkout reports existing Prettier warnings across 56 files; no broad formatting changes were included.
• scripts/build-website.sh was not run locally because this Windows host only exposes the WSL bash launcher and /bin/bash is unavailable. CI runs the website build on Ubuntu.

Notes

• Fixes Broken link on the site documentation #440.
• No runtime code changes; this only changes documentation generation.

Related Issues

Fixes #440

Check List

• I have read the Contributing Guidelines